Python Documentation contents
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* What's New in Python

  * What's New In Python 3.10

    * Summary -- Release highlights

    * New Features

      * Parenthesized context managers

      * Better error messages

        * SyntaxErrors

        * IndentationErrors

        * AttributeErrors

        * NameErrors

      * PEP 626: Precise line numbers for debugging and other tools

      * PEP 634: Structural Pattern Matching

        * Syntax and operations

        * Declarative approach

        * Simple pattern: match to a literal

          * Behavior without the wildcard

        * Patterns with a literal and variable

        * Patterns and classes

          * Patterns with positional parameters

        * Nested patterns

        * Complex patterns and the wildcard

        * Guard

        * Other Key Features

      * Optional "EncodingWarning" and "encoding="locale"" option

    * New Features Related to Type Hints

      * PEP 604: New Type Union Operator

      * PEP 612: Parameter Specification Variables

      * PEP 613: TypeAlias

      * PEP 647: User-Defined Type Guards

    * Other Language Changes

    * New Modules

    * Improved Modules

      * asyncio

      * argparse

      * array

      * asynchat, asyncore, smtpd

      * base64

      * bdb

      * bisect

      * codecs

      * collections.abc

      * contextlib

      * curses

      * dataclasses

        * __slots__

        * Keyword-only fields

      * distutils

      * doctest

      * encodings

      * fileinput

      * faulthandler

      * gc

      * glob

      * hashlib

      * hmac

      * IDLE and idlelib

      * importlib.metadata

      * inspect

      * itertools

      * linecache

      * os

      * os.path

      * pathlib

      * platform

      * pprint

      * py_compile

      * pyclbr

      * shelve

      * statistics

      * site

      * socket

      * ssl

      * sqlite3

      * sys

      * _thread

      * threading

      * traceback

      * types

      * typing

      * unittest

      * urllib.parse

      * xml

      * zipimport

    * Optimizations

    * Deprecated

    * Removed

    * Porting to Python 3.10

      * Changes in the Python syntax

      * Changes in the Python API

      * Changes in the C API

    * CPython bytecode changes

    * Build Changes

    * C API Changes

      * PEP 652: Maintaining the Stable ABI

      * New Features

      * Porting to Python 3.10

      * Deprecated

      * Removed

    * Notable security feature in 3.10.7

    * Notable security feature in 3.10.8

    * Notable Changes in 3.10.12

      * tarfile

  * What's New In Python 3.9

    * Summary -- Release highlights

    * You should check for DeprecationWarning in your code

    * New Features

      * Dictionary Merge & Update Operators

      * New String Methods to Remove Prefixes and Suffixes

      * Type Hinting Generics in Standard Collections

      * New Parser

    * Other Language Changes

    * New Modules

      * zoneinfo

      * graphlib

    * Improved Modules

      * ast

      * asyncio

      * compileall

      * concurrent.futures

      * curses

      * datetime

      * distutils

      * fcntl

      * ftplib

      * gc

      * hashlib

      * http

      * IDLE and idlelib

      * imaplib

      * importlib

      * inspect

      * ipaddress

      * math

      * multiprocessing

      * nntplib

      * os

      * pathlib

      * pdb

      * poplib

      * pprint

      * pydoc

      * random

      * signal

      * smtplib

      * socket

      * time

      * sys

      * tracemalloc

      * typing

      * unicodedata

      * venv

      * xml

    * Optimizations

    * Deprecated

    * Removed

    * Porting to Python 3.9

      * Changes in the Python API

      * Changes in the C API

      * CPython bytecode changes

    * Build Changes

    * C API Changes

      * New Features

      * Porting to Python 3.9

      * Removed

    * Notable changes in Python 3.9.1

      * typing

      * macOS 11.0 (Big Sur) and Apple Silicon Mac support

    * Notable changes in Python 3.9.2

      * collections.abc

      * urllib.parse

  * What's New In Python 3.8

    * Summary -- Release highlights

    * New Features

      * Assignment expressions

      * Positional-only parameters

      * Parallel filesystem cache for compiled bytecode files

      * Debug build uses the same ABI as release build

      * f-strings support "=" for self-documenting expressions and
        debugging

      * PEP 578: Python Runtime Audit Hooks

      * PEP 587: Python Initialization Configuration

      * PEP 590: Vectorcall: a fast calling protocol for CPython

      * Pickle protocol 5 with out-of-band data buffers

    * Other Language Changes

    * New Modules

    * Improved Modules

      * ast

      * asyncio

      * builtins

      * collections

      * cProfile

      * csv

      * curses

      * ctypes

      * datetime

      * functools

      * gc

      * gettext

      * gzip

      * IDLE and idlelib

      * inspect

      * io

      * itertools

      * json.tool

      * logging

      * math

      * mmap

      * multiprocessing

      * os

      * os.path

      * pathlib

      * pickle

      * plistlib

      * pprint

      * py_compile

      * shlex

      * shutil

      * socket

      * ssl

      * statistics

      * sys

      * tarfile

      * threading

      * tokenize

      * tkinter

      * time

      * typing

      * unicodedata

      * unittest

      * venv

      * weakref

      * xml

      * xmlrpc

    * Optimizations

    * Build and C API Changes

    * Deprecated

    * API and Feature Removals

    * Porting to Python 3.8

      * Changes in Python behavior

      * Changes in the Python API

      * Changes in the C API

      * CPython bytecode changes

      * Demos and Tools

    * Notable changes in Python 3.8.1

    * Notable changes in Python 3.8.8

    * Notable changes in Python 3.8.12

  * What's New In Python 3.7

    * Summary -- Release Highlights

    * New Features

      * PEP 563: Postponed Evaluation of Annotations

      * PEP 538: Legacy C Locale Coercion

      * PEP 540: Forced UTF-8 Runtime Mode

      * PEP 553: Built-in "breakpoint()"

      * PEP 539: New C API for Thread-Local Storage

      * PEP 562: Customization of Access to Module Attributes

      * PEP 564: New Time Functions With Nanosecond Resolution

      * PEP 565: Show DeprecationWarning in "__main__"

      * PEP 560: Core Support for "typing" module and Generic Types

      * PEP 552: Hash-based .pyc Files

      * PEP 545: Python Documentation Translations

      * Python Development Mode (-X dev)

    * Other Language Changes

    * New Modules

      * contextvars

      * dataclasses

      * importlib.resources

    * Improved Modules

      * argparse

      * asyncio

      * binascii

      * calendar

      * collections

      * compileall

      * concurrent.futures

      * contextlib

      * cProfile

      * crypt

      * datetime

      * dbm

      * decimal

      * dis

      * distutils

      * enum

      * functools

      * gc

      * hmac

      * http.client

      * http.server

      * idlelib and IDLE

      * importlib

      * io

      * ipaddress

      * itertools

      * locale

      * logging

      * math

      * mimetypes

      * msilib

      * multiprocessing

      * os

      * pathlib

      * pdb

      * py_compile

      * pydoc

      * queue

      * re

      * signal

      * socket

      * socketserver

      * sqlite3

      * ssl

      * string

      * subprocess

      * sys

      * time

      * tkinter

      * tracemalloc

      * types

      * unicodedata

      * unittest

      * unittest.mock

      * urllib.parse

      * uu

      * uuid

      * warnings

      * xml.etree

      * xmlrpc.server

      * zipapp

      * zipfile

    * C API Changes

    * Build Changes

    * Optimizations

    * Other CPython Implementation Changes

    * Deprecated Python Behavior

    * Deprecated Python modules, functions and methods

      * aifc

      * asyncio

      * collections

      * dbm

      * enum

      * gettext

      * importlib

      * locale

      * macpath

      * threading

      * socket

      * ssl

      * sunau

      * sys

      * wave

    * Deprecated functions and types of the C API

    * Platform Support Removals

    * API and Feature Removals

    * Module Removals

    * Windows-only Changes

    * Porting to Python 3.7

      * Changes in Python Behavior

      * Changes in the Python API

      * Changes in the C API

      * CPython bytecode changes

      * Windows-only Changes

      * Other CPython implementation changes

    * Notable changes in Python 3.7.1

    * Notable changes in Python 3.7.2

    * Notable changes in Python 3.7.6

    * Notable changes in Python 3.7.10

  * What's New In Python 3.6

    * Summary -- Release highlights

    * New Features

      * PEP 498: Formatted string literals

      * PEP 526: Syntax for variable annotations

      * PEP 515: Underscores in Numeric Literals

      * PEP 525: Asynchronous Generators

      * PEP 530: Asynchronous Comprehensions

      * PEP 487: Simpler customization of class creation

      * PEP 487: Descriptor Protocol Enhancements

      * PEP 519: Adding a file system path protocol

      * PEP 495: Local Time Disambiguation

      * PEP 529: Change Windows filesystem encoding to UTF-8

      * PEP 528: Change Windows console encoding to UTF-8

      * PEP 520: Preserving Class Attribute Definition Order

      * PEP 468: Preserving Keyword Argument Order

      * New *dict* implementation

      * PEP 523: Adding a frame evaluation API to CPython

      * PYTHONMALLOC environment variable

      * DTrace and SystemTap probing support

    * Other Language Changes

    * New Modules

      * secrets

    * Improved Modules

      * array

      * ast

      * asyncio

      * binascii

      * cmath

      * collections

      * concurrent.futures

      * contextlib

      * datetime

      * decimal

      * distutils

      * email

      * encodings

      * enum

      * faulthandler

      * fileinput

      * hashlib

      * http.client

      * idlelib and IDLE

      * importlib

      * inspect

      * json

      * logging

      * math

      * multiprocessing

      * os

      * pathlib

      * pdb

      * pickle

      * pickletools

      * pydoc

      * random

      * re

      * readline

      * rlcompleter

      * shlex

      * site

      * sqlite3

      * socket

      * socketserver

      * ssl

      * statistics

      * struct

      * subprocess

      * sys

      * telnetlib

      * time

      * timeit

      * tkinter

      * traceback

      * tracemalloc

      * typing

      * unicodedata

      * unittest.mock

      * urllib.request

      * urllib.robotparser

      * venv

      * warnings

      * winreg

      * winsound

      * xmlrpc.client

      * zipfile

      * zlib

    * Optimizations

    * Build and C API Changes

    * Other Improvements

    * Deprecated

      * New Keywords

      * Deprecated Python behavior

      * Deprecated Python modules, functions and methods

        * asynchat

        * asyncore

        * dbm

        * distutils

        * grp

        * importlib

        * os

        * re

        * ssl

        * tkinter

        * venv

      * Deprecated functions and types of the C API

      * Deprecated Build Options

    * Removed

      * API and Feature Removals

    * Porting to Python 3.6

      * Changes in 'python' Command Behavior

      * Changes in the Python API

      * Changes in the C API

      * CPython bytecode changes

    * Notable changes in Python 3.6.2

      * New "make regen-all" build target

      * Removal of "make touch" build target

    * Notable changes in Python 3.6.4

    * Notable changes in Python 3.6.5

    * Notable changes in Python 3.6.7

    * Notable changes in Python 3.6.10

    * Notable changes in Python 3.6.13

  * What's New In Python 3.5

    * Summary -- Release highlights

    * New Features

      * PEP 492 - Coroutines with async and await syntax

      * PEP 465 - A dedicated infix operator for matrix multiplication

      * PEP 448 - Additional Unpacking Generalizations

      * PEP 461 - percent formatting support for bytes and bytearray

      * PEP 484 - Type Hints

      * PEP 471 - os.scandir() function -- a better and faster
        directory iterator

      * PEP 475: Retry system calls failing with EINTR

      * PEP 479: Change StopIteration handling inside generators

      * PEP 485: A function for testing approximate equality

      * PEP 486: Make the Python Launcher aware of virtual
        environments

      * PEP 488: Elimination of PYO files

      * PEP 489: Multi-phase extension module initialization

    * Other Language Changes

    * New Modules

      * typing

      * zipapp

    * Improved Modules

      * argparse

      * asyncio

      * bz2

      * cgi

      * cmath

      * code

      * collections

      * collections.abc

      * compileall

      * concurrent.futures

      * configparser

      * contextlib

      * csv

      * curses

      * dbm

      * difflib

      * distutils

      * doctest

      * email

      * enum

      * faulthandler

      * functools

      * glob

      * gzip

      * heapq

      * http

      * http.client

      * idlelib and IDLE

      * imaplib

      * imghdr

      * importlib

      * inspect

      * io

      * ipaddress

      * json

      * linecache

      * locale

      * logging

      * lzma

      * math

      * multiprocessing

      * operator

      * os

      * pathlib

      * pickle

      * poplib

      * re

      * readline

      * selectors

      * shutil

      * signal

      * smtpd

      * smtplib

      * sndhdr

      * socket

      * ssl

        * Memory BIO Support

        * Application-Layer Protocol Negotiation Support

        * Other Changes

      * sqlite3

      * subprocess

      * sys

      * sysconfig

      * tarfile

      * threading

      * time

      * timeit

      * tkinter

      * traceback

      * types

      * unicodedata

      * unittest

      * unittest.mock

      * urllib

      * wsgiref

      * xmlrpc

      * xml.sax

      * zipfile

    * Other module-level changes

    * Optimizations

    * Build and C API Changes

    * Deprecated

      * New Keywords

      * Deprecated Python Behavior

      * Unsupported Operating Systems

      * Deprecated Python modules, functions and methods

    * Removed

      * API and Feature Removals

    * Porting to Python 3.5

      * Changes in Python behavior

      * Changes in the Python API

      * Changes in the C API

    * Notable changes in Python 3.5.4

      * New "make regen-all" build target

      * Removal of "make touch" build target

  * What's New In Python 3.4

    * Summary -- Release Highlights

    * New Features

      * PEP 453: Explicit Bootstrapping of PIP in Python Installations

        * Bootstrapping pip By Default

        * Documentation Changes

      * PEP 446: Newly Created File Descriptors Are Non-Inheritable

      * Improvements to Codec Handling

      * PEP 451: A ModuleSpec Type for the Import System

      * Other Language Changes

    * New Modules

      * asyncio

      * ensurepip

      * enum

      * pathlib

      * selectors

      * statistics

      * tracemalloc

    * Improved Modules

      * abc

      * aifc

      * argparse

      * audioop

      * base64

      * collections

      * colorsys

      * contextlib

      * dbm

      * dis

      * doctest

      * email

      * filecmp

      * functools

      * gc

      * glob

      * hashlib

      * hmac

      * html

      * http

      * idlelib and IDLE

      * importlib

      * inspect

      * ipaddress

      * logging

      * marshal

      * mmap

      * multiprocessing

      * operator

      * os

      * pdb

      * pickle

      * plistlib

      * poplib

      * pprint

      * pty

      * pydoc

      * re

      * resource

      * select

      * shelve

      * shutil

      * smtpd

      * smtplib

      * socket

      * sqlite3

      * ssl

      * stat

      * struct

      * subprocess

      * sunau

      * sys

      * tarfile

      * textwrap

      * threading

      * traceback

      * types

      * urllib

      * unittest

      * venv

      * wave

      * weakref

      * xml.etree

      * zipfile

    * CPython Implementation Changes

      * PEP 445: Customization of CPython Memory Allocators

      * PEP 442: Safe Object Finalization

      * PEP 456: Secure and Interchangeable Hash Algorithm

      * PEP 436: Argument Clinic

      * Other Build and C API Changes

      * Other Improvements

      * Significant Optimizations

    * Deprecated

      * Deprecations in the Python API

      * Deprecated Features

    * Removed

      * Operating Systems No Longer Supported

      * API and Feature Removals

      * Code Cleanups

    * Porting to Python 3.4

      * Changes in 'python' Command Behavior

      * Changes in the Python API

      * Changes in the C API

    * Changed in 3.4.3

      * PEP 476: Enabling certificate verification by default for
        stdlib http clients

  * What's New In Python 3.3

    * Summary -- Release highlights

    * PEP 405: Virtual Environments

    * PEP 420: Implicit Namespace Packages

    * PEP 3118: New memoryview implementation and buffer protocol
      documentation

      * Features

      * API changes

    * PEP 393: Flexible String Representation

      * Functionality

      * Performance and resource usage

    * PEP 397: Python Launcher for Windows

    * PEP 3151: Reworking the OS and IO exception hierarchy

    * PEP 380: Syntax for Delegating to a Subgenerator

    * PEP 409: Suppressing exception context

    * PEP 414: Explicit Unicode literals

    * PEP 3155: Qualified name for classes and functions

    * PEP 412: Key-Sharing Dictionary

    * PEP 362: Function Signature Object

    * PEP 421: Adding sys.implementation

      * SimpleNamespace

    * Using importlib as the Implementation of Import

      * New APIs

      * Visible Changes

    * Other Language Changes

    * A Finer-Grained Import Lock

    * Builtin functions and types

    * New Modules

      * faulthandler

      * ipaddress

      * lzma

    * Improved Modules

      * abc

      * array

      * base64

      * binascii

      * bz2

      * codecs

      * collections

      * contextlib

      * crypt

      * curses

      * datetime

      * decimal

        * Features

        * API changes

      * email

        * Policy Framework

        * Provisional Policy with New Header API

        * Other API Changes

      * ftplib

      * functools

      * gc

      * hmac

      * http

      * html

      * imaplib

      * inspect

      * io

      * itertools

      * logging

      * math

      * mmap

      * multiprocessing

      * nntplib

      * os

      * pdb

      * pickle

      * pydoc

      * re

      * sched

      * select

      * shlex

      * shutil

      * signal

      * smtpd

      * smtplib

      * socket

      * socketserver

      * sqlite3

      * ssl

      * stat

      * struct

      * subprocess

      * sys

      * tarfile

      * tempfile

      * textwrap

      * threading

      * time

      * types

      * unittest

      * urllib

      * webbrowser

      * xml.etree.ElementTree

      * zlib

    * Optimizations

    * Build and C API Changes

    * Deprecated

      * Unsupported Operating Systems

      * Deprecated Python modules, functions and methods

      * Deprecated functions and types of the C API

      * Deprecated features

    * Porting to Python 3.3

      * Porting Python code

      * Porting C code

      * Building C extensions

      * Command Line Switch Changes

  * What's New In Python 3.2

    * PEP 384: Defining a Stable ABI

    * PEP 389: Argparse Command Line Parsing Module

    * PEP 391:  Dictionary Based Configuration for Logging

    * PEP 3148:  The "concurrent.futures" module

    * PEP 3147:  PYC Repository Directories

    * PEP 3149: ABI Version Tagged .so Files

    * PEP 3333: Python Web Server Gateway Interface v1.0.1

    * Other Language Changes

    * New, Improved, and Deprecated Modules

      * email

      * elementtree

      * functools

      * itertools

      * collections

      * threading

      * datetime and time

      * math

      * abc

      * io

      * reprlib

      * logging

      * csv

      * contextlib

      * decimal and fractions

      * ftp

      * popen

      * select

      * gzip and zipfile

      * tarfile

      * hashlib

      * ast

      * os

      * shutil

      * sqlite3

      * html

      * socket

      * ssl

      * nntp

      * certificates

      * imaplib

      * http.client

      * unittest

      * random

      * poplib

      * asyncore

      * tempfile

      * inspect

      * pydoc

      * dis

      * dbm

      * ctypes

      * site

      * sysconfig

      * pdb

      * configparser

      * urllib.parse

      * mailbox

      * turtledemo

    * Multi-threading

    * Optimizations

    * Unicode

    * Codecs

    * Documentation

    * IDLE

    * Code Repository

    * Build and C API Changes

    * Porting to Python 3.2

  * What's New In Python 3.1

    * PEP 372: Ordered Dictionaries

    * PEP 378: Format Specifier for Thousands Separator

    * Other Language Changes

    * New, Improved, and Deprecated Modules

    * Optimizations

    * IDLE

    * Build and C API Changes

    * Porting to Python 3.1

  * What's New In Python 3.0

    * Common Stumbling Blocks

      * Print Is A Function

      * Views And Iterators Instead Of Lists

      * Ordering Comparisons

      * Integers

      * Text Vs. Data Instead Of Unicode Vs. 8-bit

    * Overview Of Syntax Changes

      * New Syntax

      * Changed Syntax

      * Removed Syntax

    * Changes Already Present In Python 2.6

    * Library Changes

    * **PEP 3101**: A New Approach To String Formatting

    * Changes To Exceptions

    * Miscellaneous Other Changes

      * Operators And Special Methods

      * Builtins

    * Build and C API Changes

    * Performance

    * Porting To Python 3.0

  * What's New in Python 2.7

    * The Future for Python 2.x

    * Changes to the Handling of Deprecation Warnings

    * Python 3.1 Features

    * PEP 372: Adding an Ordered Dictionary to collections

    * PEP 378: Format Specifier for Thousands Separator

    * PEP 389: The argparse Module for Parsing Command Lines

    * PEP 391: Dictionary-Based Configuration For Logging

    * PEP 3106: Dictionary Views

    * PEP 3137: The memoryview Object

    * Other Language Changes

      * Interpreter Changes

      * Optimizations

    * New and Improved Modules

      * New module: importlib

      * New module: sysconfig

      * ttk: Themed Widgets for Tk

      * Updated module: unittest

      * Updated module: ElementTree 1.3

    * Build and C API Changes

      * Capsules

      * Port-Specific Changes: Windows

      * Port-Specific Changes: Mac OS X

      * Port-Specific Changes: FreeBSD

    * Other Changes and Fixes

    * Porting to Python 2.7

    * New Features Added to Python 2.7 Maintenance Releases

      * Two new environment variables for debug mode

      * PEP 434: IDLE Enhancement Exception for All Branches

      * PEP 466: Network Security Enhancements for Python 2.7

      * PEP 477: Backport ensurepip (PEP 453) to Python 2.7

        * Bootstrapping pip By Default

        * Documentation Changes

      * PEP 476: Enabling certificate verification by default for
        stdlib http clients

      * PEP 493: HTTPS verification migration tools for Python 2.7

      * New "make regen-all" build target

      * Removal of "make touch" build target

    * Acknowledgements

  * What's New in Python 2.6

    * Python 3.0

    * Changes to the Development Process

      * New Issue Tracker: Roundup

      * New Documentation Format: reStructuredText Using Sphinx

    * PEP 343: The 'with' statement

      * Writing Context Managers

      * The contextlib module

    * PEP 366: Explicit Relative Imports From a Main Module

    * PEP 370: Per-user "site-packages" Directory

    * PEP 371: The "multiprocessing" Package

    * PEP 3101: Advanced String Formatting

    * PEP 3105: "print" As a Function

    * PEP 3110: Exception-Handling Changes

    * PEP 3112: Byte Literals

    * PEP 3116: New I/O Library

    * PEP 3118: Revised Buffer Protocol

    * PEP 3119: Abstract Base Classes

    * PEP 3127: Integer Literal Support and Syntax

    * PEP 3129: Class Decorators

    * PEP 3141: A Type Hierarchy for Numbers

      * The "fractions" Module

    * Other Language Changes

      * Optimizations

      * Interpreter Changes

    * New and Improved Modules

      * The "ast" module

      * The "future_builtins" module

      * The "json" module: JavaScript Object Notation

      * The "plistlib" module: A Property-List Parser

      * ctypes Enhancements

      * Improved SSL Support

    * Deprecations and Removals

    * Build and C API Changes

      * Port-Specific Changes: Windows

      * Port-Specific Changes: Mac OS X

      * Port-Specific Changes: IRIX

    * Porting to Python 2.6

    * Acknowledgements

  * What's New in Python 2.5

    * PEP 308: Conditional Expressions

    * PEP 309: Partial Function Application

    * PEP 314: Metadata for Python Software Packages v1.1

    * PEP 328: Absolute and Relative Imports

    * PEP 338: Executing Modules as Scripts

    * PEP 341: Unified try/except/finally

    * PEP 342: New Generator Features

    * PEP 343: The 'with' statement

      * Writing Context Managers

      * The contextlib module

    * PEP 352: Exceptions as New-Style Classes

    * PEP 353: Using ssize_t as the index type

    * PEP 357: The '__index__' method

    * Other Language Changes

      * Interactive Interpreter Changes

      * Optimizations

    * New, Improved, and Removed Modules

      * The ctypes package

      * The ElementTree package

      * The hashlib package

      * The sqlite3 package

      * The wsgiref package

    * Build and C API Changes

      * Port-Specific Changes

    * Porting to Python 2.5

    * Acknowledgements

  * What's New in Python 2.4

    * PEP 218: Built-In Set Objects

    * PEP 237: Unifying Long Integers and Integers

    * PEP 289: Generator Expressions

    * PEP 292: Simpler String Substitutions

    * PEP 318: Decorators for Functions and Methods

    * PEP 322: Reverse Iteration

    * PEP 324: New subprocess Module

    * PEP 327: Decimal Data Type

      * Why is Decimal needed?

      * The "Decimal" type

      * The "Context" type

    * PEP 328: Multi-line Imports

    * PEP 331: Locale-Independent Float/String Conversions

    * Other Language Changes

      * Optimizations

    * New, Improved, and Deprecated Modules

      * cookielib

      * doctest

    * Build and C API Changes

      * Port-Specific Changes

    * Porting to Python 2.4

    * Acknowledgements

  * What's New in Python 2.3

    * PEP 218: A Standard Set Datatype

    * PEP 255: Simple Generators

    * PEP 263: Source Code Encodings

    * PEP 273: Importing Modules from ZIP Archives

    * PEP 277: Unicode file name support for Windows NT

    * PEP 278: Universal Newline Support

    * PEP 279: enumerate()

    * PEP 282: The logging Package

    * PEP 285: A Boolean Type

    * PEP 293: Codec Error Handling Callbacks

    * PEP 301: Package Index and Metadata for Distutils

    * PEP 302: New Import Hooks

    * PEP 305: Comma-separated Files

    * PEP 307: Pickle Enhancements

    * Extended Slices

    * Other Language Changes

      * String Changes

      * Optimizations

    * New, Improved, and Deprecated Modules

      * Date/Time Type

      * The optparse Module

    * Pymalloc: A Specialized Object Allocator

    * Build and C API Changes

      * Port-Specific Changes

    * Other Changes and Fixes

    * Porting to Python 2.3

    * Acknowledgements

  * What's New in Python 2.2

    * Introduction

    * PEPs 252 and 253: Type and Class Changes

      * Old and New Classes

      * Descriptors

      * Multiple Inheritance: The Diamond Rule

      * Attribute Access

      * Related Links

    * PEP 234: Iterators

    * PEP 255: Simple Generators

    * PEP 237: Unifying Long Integers and Integers

    * PEP 238: Changing the Division Operator

    * Unicode Changes

    * PEP 227: Nested Scopes

    * New and Improved Modules

    * Interpreter Changes and Fixes

    * Other Changes and Fixes

    * Acknowledgements

  * What's New in Python 2.1

    * Introduction

    * PEP 227: Nested Scopes

    * PEP 236: __future__ Directives

    * PEP 207: Rich Comparisons

    * PEP 230: Warning Framework

    * PEP 229: New Build System

    * PEP 205: Weak References

    * PEP 232: Function Attributes

    * PEP 235: Importing Modules on Case-Insensitive Platforms

    * PEP 217: Interactive Display Hook

    * PEP 208: New Coercion Model

    * PEP 241: Metadata in Python Packages

    * New and Improved Modules

    * Other Changes and Fixes

    * Acknowledgements

  * What's New in Python 2.0

    * Introduction

    * What About Python 1.6?

    * New Development Process

    * Unicode

    * List Comprehensions

    * Augmented Assignment

    * String Methods

    * Garbage Collection of Cycles

    * Other Core Changes

      * Minor Language Changes

      * Changes to Built-in Functions

    * Porting to 2.0

    * Extending/Embedding Changes

    * Distutils: Making Modules Easy to Install

    * XML Modules

      * SAX2 Support

      * DOM Support

      * Relationship to PyXML

    * Module changes

    * New modules

    * IDLE Improvements

    * Deleted and Deprecated Modules

    * Acknowledgements

  * Changelog

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* The Python Tutorial

  * 1. Whetting Your Appetite

  * 2. Using the Python Interpreter

    * 2.1. Invoking the Interpreter

      * 2.1.1. Argument Passing

      * 2.1.2. Interactive Mode

    * 2.2. The Interpreter and Its Environment

      * 2.2.1. Source Code Encoding

  * 3. An Informal Introduction to Python

    * 3.1. Using Python as a Calculator

      * 3.1.1. Numbers

      * 3.1.2. Strings

      * 3.1.3. Lists

    * 3.2. First Steps Towards Programming

  * 4. More Control Flow Tools

    * 4.1. "if" Statements

    * 4.2. "for" Statements

    * 4.3. The "range()" Function

    * 4.4. "break" and "continue" Statements, and "else" Clauses on
      Loops

    * 4.5. "pass" Statements

    * 4.6. "match" Statements

    * 4.7. Defining Functions

    * 4.8. More on Defining Functions

      * 4.8.1. Default Argument Values

      * 4.8.2. Keyword Arguments

      * 4.8.3. Special parameters

        * 4.8.3.1. Positional-or-Keyword Arguments

        * 4.8.3.2. Positional-Only Parameters

        * 4.8.3.3. Keyword-Only Arguments

        * 4.8.3.4. Function Examples

        * 4.8.3.5. Recap

      * 4.8.4. Arbitrary Argument Lists

      * 4.8.5. Unpacking Argument Lists

      * 4.8.6. Lambda Expressions

      * 4.8.7. Documentation Strings

      * 4.8.8. Function Annotations

    * 4.9. Intermezzo: Coding Style

  * 5. Data Structures

    * 5.1. More on Lists

      * 5.1.1. Using Lists as Stacks

      * 5.1.2. Using Lists as Queues

      * 5.1.3. List Comprehensions

      * 5.1.4. Nested List Comprehensions

    * 5.2. The "del" statement

    * 5.3. Tuples and Sequences

    * 5.4. Sets

    * 5.5. Dictionaries

    * 5.6. Looping Techniques

    * 5.7. More on Conditions

    * 5.8. Comparing Sequences and Other Types

  * 6. Modules

    * 6.1. More on Modules

      * 6.1.1. Executing modules as scripts

      * 6.1.2. The Module Search Path

      * 6.1.3. "Compiled" Python files

    * 6.2. Standard Modules

    * 6.3. The "dir()" Function

    * 6.4. Packages

      * 6.4.1. Importing * From a Package

      * 6.4.2. Intra-package References

      * 6.4.3. Packages in Multiple Directories

  * 7. Input and Output

    * 7.1. Fancier Output Formatting

      * 7.1.1. Formatted String Literals

      * 7.1.2. The String format() Method

      * 7.1.3. Manual String Formatting

      * 7.1.4. Old string formatting

    * 7.2. Reading and Writing Files

      * 7.2.1. Methods of File Objects

      * 7.2.2. Saving structured data with "json"

  * 8. Errors and Exceptions

    * 8.1. Syntax Errors

    * 8.2. Exceptions

    * 8.3. Handling Exceptions

    * 8.4. Raising Exceptions

    * 8.5. Exception Chaining

    * 8.6. User-defined Exceptions

    * 8.7. Defining Clean-up Actions

    * 8.8. Predefined Clean-up Actions

  * 9. Classes

    * 9.1. A Word About Names and Objects

    * 9.2. Python Scopes and Namespaces

      * 9.2.1. Scopes and Namespaces Example

    * 9.3. A First Look at Classes

      * 9.3.1. Class Definition Syntax

      * 9.3.2. Class Objects

      * 9.3.3. Instance Objects

      * 9.3.4. Method Objects

      * 9.3.5. Class and Instance Variables

    * 9.4. Random Remarks

    * 9.5. Inheritance

      * 9.5.1. Multiple Inheritance

    * 9.6. Private Variables

    * 9.7. Odds and Ends

    * 9.8. Iterators

    * 9.9. Generators

    * 9.10. Generator Expressions

  * 10. Brief Tour of the Standard Library

    * 10.1. Operating System Interface

    * 10.2. File Wildcards

    * 10.3. Command Line Arguments

    * 10.4. Error Output Redirection and Program Termination

    * 10.5. String Pattern Matching

    * 10.6. Mathematics

    * 10.7. Internet Access

    * 10.8. Dates and Times

    * 10.9. Data Compression

    * 10.10. Performance Measurement

    * 10.11. Quality Control

    * 10.12. Batteries Included

  * 11. Brief Tour of the Standard Library --- Part II

    * 11.1. Output Formatting

    * 11.2. Templating

    * 11.3. Working with Binary Data Record Layouts

    * 11.4. Multi-threading

    * 11.5. Logging

    * 11.6. Weak References

    * 11.7. Tools for Working with Lists

    * 11.8. Decimal Floating Point Arithmetic

  * 12. Virtual Environments and Packages

    * 12.1. Introduction

    * 12.2. Creating Virtual Environments

    * 12.3. Managing Packages with pip

  * 13. What Now?

  * 14. Interactive Input Editing and History Substitution

    * 14.1. Tab Completion and History Editing

    * 14.2. Alternatives to the Interactive Interpreter

  * 15. Floating Point Arithmetic:  Issues and Limitations

    * 15.1. Representation Error

  * 16. Appendix

    * 16.1. Interactive Mode

      * 16.1.1. Error Handling

      * 16.1.2. Executable Python Scripts

      * 16.1.3. The Interactive Startup File

      * 16.1.4. The Customization Modules

* Python Setup and Usage

  * 1. Command line and environment

    * 1.1. Command line

      * 1.1.1. Interface options

      * 1.1.2. Generic options

      * 1.1.3. Miscellaneous options

      * 1.1.4. Options you shouldn't use

    * 1.2. Environment variables

      * 1.2.1. Debug-mode variables

  * 2. Using Python on Unix platforms

    * 2.1. Getting and installing the latest version of Python

      * 2.1.1. On Linux

      * 2.1.2. On FreeBSD and OpenBSD

      * 2.1.3. On OpenSolaris

    * 2.2. Building Python

    * 2.3. Python-related paths and files

    * 2.4. Miscellaneous

    * 2.5. Custom OpenSSL

  * 3. Configure Python

    * 3.1. Configure Options

      * 3.1.1. General Options

      * 3.1.2. Install Options

      * 3.1.3. Performance options

      * 3.1.4. Python Debug Build

      * 3.1.5. Debug options

      * 3.1.6. Linker options

      * 3.1.7. Libraries options

      * 3.1.8. Security Options

      * 3.1.9. macOS Options

    * 3.2. Python Build System

      * 3.2.1. Main files of the build system

      * 3.2.2. Main build steps

      * 3.2.3. Main Makefile targets

      * 3.2.4. C extensions

    * 3.3. Compiler and linker flags

      * 3.3.1. Preprocessor flags

      * 3.3.2. Compiler flags

      * 3.3.3. Linker flags

  * 4. Using Python on Windows

    * 4.1. The full installer

      * 4.1.1. Installation steps

      * 4.1.2. Removing the MAX_PATH Limitation

      * 4.1.3. Installing Without UI

      * 4.1.4. Installing Without Downloading

      * 4.1.5. Modifying an install

    * 4.2. The Microsoft Store package

      * 4.2.1. Known issues

        * 4.2.1.1. Redirection of local data, registry, and temporary
          paths

    * 4.3. The nuget.org packages

    * 4.4. The embeddable package

      * 4.4.1. Python Application

      * 4.4.2. Embedding Python

    * 4.5. Alternative bundles

    * 4.6. Configuring Python

      * 4.6.1. Excursus: Setting environment variables

      * 4.6.2. Finding the Python executable

    * 4.7. UTF-8 mode

    * 4.8. Python Launcher for Windows

      * 4.8.1. Getting started

        * 4.8.1.1. From the command-line

        * 4.8.1.2. Virtual environments

        * 4.8.1.3. From a script

        * 4.8.1.4. From file associations

      * 4.8.2. Shebang Lines

      * 4.8.3. Arguments in shebang lines

      * 4.8.4. Customization

        * 4.8.4.1. Customization via INI files

        * 4.8.4.2. Customizing default Python versions

      * 4.8.5. Diagnostics

    * 4.9. Finding modules

    * 4.10. Additional modules

      * 4.10.1. PyWin32

      * 4.10.2. cx_Freeze

    * 4.11. Compiling Python on Windows

    * 4.12. Other Platforms

  * 5. Using Python on a Mac

    * 5.1. Getting and Installing MacPython

      * 5.1.1. How to run a Python script

      * 5.1.2. Running scripts with a GUI

      * 5.1.3. Configuration

    * 5.2. The IDE

    * 5.3. Installing Additional Python Packages

    * 5.4. GUI Programming on the Mac

    * 5.5. Distributing Python Applications on the Mac

    * 5.6. Other Resources

  * 6. Editors and IDEs

* The Python Language Reference

  * 1. Introduction

    * 1.1. Alternate Implementations

    * 1.2. Notation

  * 2. Lexical analysis

    * 2.1. Line structure

      * 2.1.1. Logical lines

      * 2.1.2. Physical lines

      * 2.1.3. Comments

      * 2.1.4. Encoding declarations

      * 2.1.5. Explicit line joining

      * 2.1.6. Implicit line joining

      * 2.1.7. Blank lines

      * 2.1.8. Indentation

      * 2.1.9. Whitespace between tokens

    * 2.2. Other tokens

    * 2.3. Identifiers and keywords

      * 2.3.1. Keywords

      * 2.3.2. Soft Keywords

      * 2.3.3. Reserved classes of identifiers

    * 2.4. Literals

      * 2.4.1. String and Bytes literals

      * 2.4.2. String literal concatenation

      * 2.4.3. Formatted string literals

      * 2.4.4. Numeric literals

      * 2.4.5. Integer literals

      * 2.4.6. Floating point literals

      * 2.4.7. Imaginary literals

    * 2.5. Operators

    * 2.6. Delimiters

  * 3. Data model

    * 3.1. Objects, values and types

    * 3.2. The standard type hierarchy

    * 3.3. Special method names

      * 3.3.1. Basic customization

      * 3.3.2. Customizing attribute access

        * 3.3.2.1. Customizing module attribute access

        * 3.3.2.2. Implementing Descriptors

        * 3.3.2.3. Invoking Descriptors

        * 3.3.2.4. __slots__

          * 3.3.2.4.1. Notes on using *__slots__*

      * 3.3.3. Customizing class creation

        * 3.3.3.1. Metaclasses

        * 3.3.3.2. Resolving MRO entries

        * 3.3.3.3. Determining the appropriate metaclass

        * 3.3.3.4. Preparing the class namespace

        * 3.3.3.5. Executing the class body

        * 3.3.3.6. Creating the class object

        * 3.3.3.7. Uses for metaclasses

      * 3.3.4. Customizing instance and subclass checks

      * 3.3.5. Emulating generic types

        * 3.3.5.1. The purpose of *__class_getitem__*

        * 3.3.5.2. *__class_getitem__* versus *__getitem__*

      * 3.3.6. Emulating callable objects

      * 3.3.7. Emulating container types

      * 3.3.8. Emulating numeric types

      * 3.3.9. With Statement Context Managers

      * 3.3.10. Customizing positional arguments in class pattern
        matching

      * 3.3.11. Special method lookup

    * 3.4. Coroutines

      * 3.4.1. Awaitable Objects

      * 3.4.2. Coroutine Objects

      * 3.4.3. Asynchronous Iterators

      * 3.4.4. Asynchronous Context Managers

  * 4. Execution model

    * 4.1. Structure of a program

    * 4.2. Naming and binding

      * 4.2.1. Binding of names

      * 4.2.2. Resolution of names

      * 4.2.3. Builtins and restricted execution

      * 4.2.4. Interaction with dynamic features

    * 4.3. Exceptions

  * 5. The import system

    * 5.1. "importlib"

    * 5.2. Packages

      * 5.2.1. Regular packages

      * 5.2.2. Namespace packages

    * 5.3. Searching

      * 5.3.1. The module cache

      * 5.3.2. Finders and loaders

      * 5.3.3. Import hooks

      * 5.3.4. The meta path

    * 5.4. Loading

      * 5.4.1. Loaders

      * 5.4.2. Submodules

      * 5.4.3. Module spec

      * 5.4.4. Import-related module attributes

      * 5.4.5. module.__path__

      * 5.4.6. Module reprs

      * 5.4.7. Cached bytecode invalidation

    * 5.5. The Path Based Finder

      * 5.5.1. Path entry finders

      * 5.5.2. Path entry finder protocol

    * 5.6. Replacing the standard import system

    * 5.7. Package Relative Imports

    * 5.8. Special considerations for __main__

      * 5.8.1. __main__.__spec__

    * 5.9. References

  * 6. Expressions

    * 6.1. Arithmetic conversions

    * 6.2. Atoms

      * 6.2.1. Identifiers (Names)

      * 6.2.2. Literals

      * 6.2.3. Parenthesized forms

      * 6.2.4. Displays for lists, sets and dictionaries

      * 6.2.5. List displays

      * 6.2.6. Set displays

      * 6.2.7. Dictionary displays

      * 6.2.8. Generator expressions

      * 6.2.9. Yield expressions

        * 6.2.9.1. Generator-iterator methods

        * 6.2.9.2. Examples

        * 6.2.9.3. Asynchronous generator functions

        * 6.2.9.4. Asynchronous generator-iterator methods

    * 6.3. Primaries

      * 6.3.1. Attribute references

      * 6.3.2. Subscriptions

      * 6.3.3. Slicings

      * 6.3.4. Calls

    * 6.4. Await expression

    * 6.5. The power operator

    * 6.6. Unary arithmetic and bitwise operations

    * 6.7. Binary arithmetic operations

    * 6.8. Shifting operations

    * 6.9. Binary bitwise operations

    * 6.10. Comparisons

      * 6.10.1. Value comparisons

      * 6.10.2. Membership test operations

      * 6.10.3. Identity comparisons

    * 6.11. Boolean operations

    * 6.12. Assignment expressions

    * 6.13. Conditional expressions

    * 6.14. Lambdas

    * 6.15. Expression lists

    * 6.16. Evaluation order

    * 6.17. Operator precedence

  * 7. Simple statements

    * 7.1. Expression statements

    * 7.2. Assignment statements

      * 7.2.1. Augmented assignment statements

      * 7.2.2. Annotated assignment statements

    * 7.3. The "assert" statement

    * 7.4. The "pass" statement

    * 7.5. The "del" statement

    * 7.6. The "return" statement

    * 7.7. The "yield" statement

    * 7.8. The "raise" statement

    * 7.9. The "break" statement

    * 7.10. The "continue" statement

    * 7.11. The "import" statement

      * 7.11.1. Future statements

    * 7.12. The "global" statement

    * 7.13. The "nonlocal" statement

  * 8. Compound statements

    * 8.1. The "if" statement

    * 8.2. The "while" statement

    * 8.3. The "for" statement

    * 8.4. The "try" statement

    * 8.5. The "with" statement

    * 8.6. The "match" statement

      * 8.6.1. Overview

      * 8.6.2. Guards

      * 8.6.3. Irrefutable Case Blocks

      * 8.6.4. Patterns

        * 8.6.4.1. OR Patterns

        * 8.6.4.2. AS Patterns

        * 8.6.4.3. Literal Patterns

        * 8.6.4.4. Capture Patterns

        * 8.6.4.5. Wildcard Patterns

        * 8.6.4.6. Value Patterns

        * 8.6.4.7. Group Patterns

        * 8.6.4.8. Sequence Patterns

        * 8.6.4.9. Mapping Patterns

        * 8.6.4.10. Class Patterns

    * 8.7. Function definitions

    * 8.8. Class definitions

    * 8.9. Coroutines

      * 8.9.1. Coroutine function definition

      * 8.9.2. The "async for" statement

      * 8.9.3. The "async with" statement

  * 9. Top-level components

    * 9.1. Complete Python programs

    * 9.2. File input

    * 9.3. Interactive input

    * 9.4. Expression input

  * 10. Full Grammar specification

* The Python Standard Library

  * Introduction

    * Notes on availability

  * Built-in Functions

  * Built-in Constants

    * Constants added by the "site" module

  * Built-in Types

    * Truth Value Testing

    * Boolean Operations --- "and", "or", "not"

    * Comparisons

    * Numeric Types --- "int", "float", "complex"

      * Bitwise Operations on Integer Types

      * Additional Methods on Integer Types

      * Additional Methods on Float

      * Hashing of numeric types

    * Iterator Types

      * Generator Types

    * Sequence Types --- "list", "tuple", "range"

      * Common Sequence Operations

      * Immutable Sequence Types

      * Mutable Sequence Types

      * Lists

      * Tuples

      * Ranges

    * Text Sequence Type --- "str"

      * String Methods

      * "printf"-style String Formatting

    * Binary Sequence Types --- "bytes", "bytearray", "memoryview"

      * Bytes Objects

      * Bytearray Objects

      * Bytes and Bytearray Operations

      * "printf"-style Bytes Formatting

      * Memory Views

    * Set Types --- "set", "frozenset"

    * Mapping Types --- "dict"

      * Dictionary view objects

    * Context Manager Types

    * Type Annotation Types --- *Generic Alias*, *Union*

      * Generic Alias Type

        * Standard Generic Classes

        * Special Attributes of "GenericAlias" objects

      * Union Type

    * Other Built-in Types

      * Modules

      * Classes and Class Instances

      * Functions

      * Methods

      * Code Objects

      * Type Objects

      * The Null Object

      * The Ellipsis Object

      * The NotImplemented Object

      * Boolean Values

      * Internal Objects

    * Special Attributes

    * Integer string conversion length limitation

      * Affected APIs

      * Configuring the limit

      * Recommended configuration

  * Built-in Exceptions

    * Exception context

    * Inheriting from built-in exceptions

    * Base classes

    * Concrete exceptions

      * OS exceptions

    * Warnings

    * Exception hierarchy

  * Text Processing Services

    * "string" --- Common string operations

      * String constants

      * Custom String Formatting

      * Format String Syntax

        * Format Specification Mini-Language

        * Format examples

      * Template strings

      * Helper functions

    * "re" --- Regular expression operations

      * Regular Expression Syntax

      * Module Contents

        * Flags

        * Functions

        * Exceptions

      * Regular Expression Objects

      * Match Objects

      * Regular Expression Examples

        * Checking for a Pair

        * Simulating scanf()

        * search() vs. match()

        * Making a Phonebook

        * Text Munging

        * Finding all Adverbs

        * Finding all Adverbs and their Positions

        * Raw String Notation

        * Writing a Tokenizer

    * "difflib" --- Helpers for computing deltas

      * SequenceMatcher Objects

      * SequenceMatcher Examples

      * Differ Objects

      * Differ Example

      * A command-line interface to difflib

    * "textwrap" --- Text wrapping and filling

    * "unicodedata" --- Unicode Database

    * "stringprep" --- Internet String Preparation

    * "readline" --- GNU readline interface

      * Init file

      * Line buffer

      * History file

      * History list

      * Startup hooks

      * Completion

      * Example

    * "rlcompleter" --- Completion function for GNU readline

      * Completer Objects

  * Binary Data Services

    * "struct" --- Interpret bytes as packed binary data

      * Functions and Exceptions

      * Format Strings

        * Byte Order, Size, and Alignment

        * Format Characters

        * Examples

      * Applications

        * Native Formats

        * Standard Formats

      * Classes

    * "codecs" --- Codec registry and base classes

      * Codec Base Classes

        * Error Handlers

        * Stateless Encoding and Decoding

        * Incremental Encoding and Decoding

          * IncrementalEncoder Objects

          * IncrementalDecoder Objects

        * Stream Encoding and Decoding

          * StreamWriter Objects

          * StreamReader Objects

          * StreamReaderWriter Objects

          * StreamRecoder Objects

      * Encodings and Unicode

      * Standard Encodings

      * Python Specific Encodings

        * Text Encodings

        * Binary Transforms

        * Text Transforms

      * "encodings.idna" --- Internationalized Domain Names in
        Applications

      * "encodings.mbcs" --- Windows ANSI codepage

      * "encodings.utf_8_sig" --- UTF-8 codec with BOM signature

  * Data Types

    * "datetime" --- Basic date and time types

      * Aware and Naive Objects

      * Constants

      * Available Types

        * Common Properties

        * Determining if an Object is Aware or Naive

      * "timedelta" Objects

        * Examples of usage: "timedelta"

      * "date" Objects

        * Examples of Usage: "date"

      * "datetime" Objects

        * Examples of Usage: "datetime"

      * "time" Objects

        * Examples of Usage: "time"

      * "tzinfo" Objects

      * "timezone" Objects

      * "strftime()" and "strptime()" Behavior

        * "strftime()" and "strptime()" Format Codes

        * Technical Detail

    * "zoneinfo" --- IANA time zone support

      * Using "ZoneInfo"

      * Data sources

        * Configuring the data sources

          * Compile-time configuration

          * Environment configuration

          * Runtime configuration

      * The "ZoneInfo" class

        * String representations

        * Pickle serialization

      * Functions

      * Globals

      * Exceptions and warnings

    * "calendar" --- General calendar-related functions

    * "collections" --- Container datatypes

      * "ChainMap" objects

        * "ChainMap" Examples and Recipes

      * "Counter" objects

      * "deque" objects

        * "deque" Recipes

      * "defaultdict" objects

        * "defaultdict" Examples

      * "namedtuple()" Factory Function for Tuples with Named Fields

      * "OrderedDict" objects

        * "OrderedDict" Examples and Recipes

      * "UserDict" objects

      * "UserList" objects

      * "UserString" objects

    * "collections.abc" --- Abstract Base Classes for Containers

      * Collections Abstract Base Classes

      * Collections Abstract Base Classes -- Detailed Descriptions

      * Examples and Recipes

    * "heapq" --- Heap queue algorithm

      * Basic Examples

      * Priority Queue Implementation Notes

      * Theory

    * "bisect" --- Array bisection algorithm

      * Performance Notes

      * Searching Sorted Lists

      * Examples

    * "array" --- Efficient arrays of numeric values

    * "weakref" --- Weak references

      * Weak Reference Objects

      * Example

      * Finalizer Objects

      * Comparing finalizers with "__del__()" methods

    * "types" --- Dynamic type creation and names for built-in types

      * Dynamic Type Creation

      * Standard Interpreter Types

      * Additional Utility Classes and Functions

      * Coroutine Utility Functions

    * "copy" --- Shallow and deep copy operations

    * "pprint" --- Data pretty printer

      * PrettyPrinter Objects

      * Example

    * "reprlib" --- Alternate "repr()" implementation

      * Repr Objects

      * Subclassing Repr Objects

    * "enum" --- Support for enumerations

      * Module Contents

      * Creating an Enum

      * Programmatic access to enumeration members and their
        attributes

      * Duplicating enum members and values

      * Ensuring unique enumeration values

      * Using automatic values

      * Iteration

      * Comparisons

      * Allowed members and attributes of enumerations

      * Restricted Enum subclassing

      * Pickling

      * Functional API

      * Derived Enumerations

        * IntEnum

        * IntFlag

        * Flag

        * Others

      * When to use "__new__()" vs. "__init__()"

      * Interesting examples

        * Omitting values

          * Using "auto"

          * Using "object"

          * Using a descriptive string

          * Using a custom "__new__()"

        * OrderedEnum

        * DuplicateFreeEnum

        * Planet

        * TimePeriod

      * How are Enums different?

        * Enum Classes

        * Enum Members (aka instances)

        * Finer Points

          * Supported "__dunder__" names

          * Supported "_sunder_" names

          * _Private__names

          * "Enum" member type

          * Boolean value of "Enum" classes and members

          * "Enum" classes with methods

          * Combining members of "Flag"

    * "graphlib" --- Functionality to operate with graph-like
      structures

      * Exceptions

  * Numeric and Mathematical Modules

    * "numbers" --- Numeric abstract base classes

      * The numeric tower

      * Notes for type implementors

        * Adding More Numeric ABCs

        * Implementing the arithmetic operations

    * "math" --- Mathematical functions

      * Number-theoretic and representation functions

      * Power and logarithmic functions

      * Trigonometric functions

      * Angular conversion

      * Hyperbolic functions

      * Special functions

      * Constants

    * "cmath" --- Mathematical functions for complex numbers

      * Conversions to and from polar coordinates

      * Power and logarithmic functions

      * Trigonometric functions

      * Hyperbolic functions

      * Classification functions

      * Constants

    * "decimal" --- Decimal fixed point and floating point arithmetic

      * Quick-start Tutorial

      * Decimal objects

        * Logical operands

      * Context objects

      * Constants

      * Rounding modes

      * Signals

      * Floating Point Notes

        * Mitigating round-off error with increased precision

        * Special values

      * Working with threads

      * Recipes

      * Decimal FAQ

    * "fractions" --- Rational numbers

    * "random" --- Generate pseudo-random numbers

      * Bookkeeping functions

      * Functions for bytes

      * Functions for integers

      * Functions for sequences

      * Real-valued distributions

      * Alternative Generator

      * Notes on Reproducibility

      * Examples

      * Recipes

    * "statistics" --- Mathematical statistics functions

      * Averages and measures of central location

      * Measures of spread

      * Statistics for relations between two inputs

      * Function details

      * Exceptions

      * "NormalDist" objects

        * "NormalDist" Examples and Recipes

  * Functional Programming Modules

    * "itertools" --- Functions creating iterators for efficient
      looping

      * Itertool functions

      * Itertools Recipes

    * "functools" --- Higher-order functions and operations on
      callable objects

      * "partial" Objects

    * "operator" --- Standard operators as functions

      * Mapping Operators to Functions

      * In-place Operators

  * File and Directory Access

    * "pathlib" --- Object-oriented filesystem paths

      * Basic use

      * Pure paths

        * General properties

        * Operators

        * Accessing individual parts

        * Methods and properties

      * Concrete paths

        * Methods

      * Correspondence to tools in the "os" module

    * "os.path" --- Common pathname manipulations

    * "fileinput" --- Iterate over lines from multiple input streams

    * "stat" --- Interpreting "stat()" results

    * "filecmp" --- File and Directory Comparisons

      * The "dircmp" class

    * "tempfile" --- Generate temporary files and directories

      * Examples

      * Deprecated functions and variables

    * "glob" --- Unix style pathname pattern expansion

    * "fnmatch" --- Unix filename pattern matching

    * "linecache" --- Random access to text lines

    * "shutil" --- High-level file operations

      * Directory and files operations

        * Platform-dependent efficient copy operations

        * copytree example

        * rmtree example

      * Archiving operations

        * Archiving example

        * Archiving example with *base_dir*

      * Querying the size of the output terminal

  * Data Persistence

    * "pickle" --- Python object serialization

      * Relationship to other Python modules

        * Comparison with "marshal"

        * Comparison with "json"

      * Data stream format

      * Module Interface

      * What can be pickled and unpickled?

      * Pickling Class Instances

        * Persistence of External Objects

        * Dispatch Tables

        * Handling Stateful Objects

      * Custom Reduction for Types, Functions, and Other Objects

      * Out-of-band Buffers

        * Provider API

        * Consumer API

        * Example

      * Restricting Globals

      * Performance

      * Examples

    * "copyreg" --- Register "pickle" support functions

      * Example

    * "shelve" --- Python object persistence

      * Restrictions

      * Example

    * "marshal" --- Internal Python object serialization

    * "dbm" --- Interfaces to Unix "databases"

      * "dbm.gnu" --- GNU's reinterpretation of dbm

      * "dbm.ndbm" --- Interface based on ndbm

      * "dbm.dumb" --- Portable DBM implementation

    * "sqlite3" --- DB-API 2.0 interface for SQLite databases

      * Tutorial

      * Reference

        * Module functions

        * Module constants

        * Connection objects

        * Cursor objects

        * Row objects

        * PrepareProtocol objects

        * Exceptions

        * SQLite and Python types

        * Default adapters and converters

      * How-to guides

        * How to use placeholders to bind values in SQL queries

        * How to adapt custom Python types to SQLite values

          * How to write adaptable objects

          * How to register adapter callables

        * How to convert SQLite values to custom Python types

        * Adapter and converter recipes

        * How to use connection shortcut methods

        * How to use the connection context manager

        * How to work with SQLite URIs

        * How to create and use row factories

      * Explanation

        * Transaction control

  * Data Compression and Archiving

    * "zlib" --- Compression compatible with **gzip**

    * "gzip" --- Support for **gzip** files

      * Examples of usage

      * Command Line Interface

        * Command line options

    * "bz2" --- Support for **bzip2** compression

      * (De)compression of files

      * Incremental (de)compression

      * One-shot (de)compression

      * Examples of usage

    * "lzma" --- Compression using the LZMA algorithm

      * Reading and writing compressed files

      * Compressing and decompressing data in memory

      * Miscellaneous

      * Specifying custom filter chains

      * Examples

    * "zipfile" --- Work with ZIP archives

      * ZipFile Objects

      * Path Objects

      * PyZipFile Objects

      * ZipInfo Objects

      * Command-Line Interface

        * Command-line options

      * Decompression pitfalls

        * From file itself

        * File System limitations

        * Resources limitations

        * Interruption

        * Default behaviors of extraction

    * "tarfile" --- Read and write tar archive files

      * TarFile Objects

      * TarInfo Objects

      * Extraction filters

        * Default named filters

        * Filter errors

        * Hints for further verification

        * Supporting older Python versions

        * Stateful extraction filter example

      * Command-Line Interface

        * Command-line options

      * Examples

      * Supported tar formats

      * Unicode issues

  * File Formats

    * "csv" --- CSV File Reading and Writing

      * Module Contents

      * Dialects and Formatting Parameters

      * Reader Objects

      * Writer Objects

      * Examples

    * "configparser" --- Configuration file parser

      * Quick Start

      * Supported Datatypes

      * Fallback Values

      * Supported INI File Structure

      * Interpolation of values

      * Mapping Protocol Access

      * Customizing Parser Behaviour

      * Legacy API Examples

      * ConfigParser Objects

      * RawConfigParser Objects

      * Exceptions

    * "netrc" --- netrc file processing

      * netrc Objects

    * "plistlib" --- Generate and parse Apple ".plist" files

      * Examples

  * Cryptographic Services

    * "hashlib" --- Secure hashes and message digests

      * Hash algorithms

      * SHAKE variable length digests

      * Key derivation

      * BLAKE2

        * Creating hash objects

        * Constants

        * Examples

          * Simple hashing

          * Using different digest sizes

          * Keyed hashing

          * Randomized hashing

          * Personalization

          * Tree mode

        * Credits

    * "hmac" --- Keyed-Hashing for Message Authentication

    * "secrets" --- Generate secure random numbers for managing
      secrets

      * Random numbers

      * Generating tokens

        * How many bytes should tokens use?

      * Other functions

      * Recipes and best practices

  * Generic Operating System Services

    * "os" --- Miscellaneous operating system interfaces

      * File Names, Command Line Arguments, and Environment Variables

      * Python UTF-8 Mode

      * Process Parameters

      * File Object Creation

      * File Descriptor Operations

        * Querying the size of a terminal

        * Inheritance of File Descriptors

      * Files and Directories

        * Linux extended attributes

      * Process Management

      * Interface to the scheduler

      * Miscellaneous System Information

      * Random numbers

    * "io" --- Core tools for working with streams

      * Overview

        * Text I/O

        * Binary I/O

        * Raw I/O

      * Text Encoding

        * Opt-in EncodingWarning

      * High-level Module Interface

      * Class hierarchy

        * I/O Base Classes

        * Raw File I/O

        * Buffered Streams

        * Text I/O

      * Performance

        * Binary I/O

        * Text I/O

        * Multi-threading

        * Reentrancy

    * "time" --- Time access and conversions

      * Functions

      * Clock ID Constants

      * Timezone Constants

    * "argparse" --- Parser for command-line options, arguments and
      sub-commands

      * Example

        * Creating a parser

        * Adding arguments

        * Parsing arguments

      * ArgumentParser objects

        * prog

        * usage

        * description

        * epilog

        * parents

        * formatter_class

        * prefix_chars

        * fromfile_prefix_chars

        * argument_default

        * allow_abbrev

        * conflict_handler

        * add_help

        * exit_on_error

      * The add_argument() method

        * name or flags

        * action

        * nargs

        * const

        * default

        * type

        * choices

        * required

        * help

        * metavar

        * dest

        * Action classes

      * The parse_args() method

        * Option value syntax

        * Invalid arguments

        * Arguments containing "-"

        * Argument abbreviations (prefix matching)

        * Beyond "sys.argv"

        * The Namespace object

      * Other utilities

        * Sub-commands

        * FileType objects

        * Argument groups

        * Mutual exclusion

        * Parser defaults

        * Printing help

        * Partial parsing

        * Customizing file parsing

        * Exiting methods

        * Intermixed parsing

      * Upgrading optparse code

    * "getopt" --- C-style parser for command line options

    * "logging" --- Logging facility for Python

      * Logger Objects

      * Logging Levels

      * Handler Objects

      * Formatter Objects

      * Filter Objects

      * LogRecord Objects

      * LogRecord attributes

      * LoggerAdapter Objects

      * Thread Safety

      * Module-Level Functions

      * Module-Level Attributes

      * Integration with the warnings module

    * "logging.config" --- Logging configuration

      * Configuration functions

      * Security considerations

      * Configuration dictionary schema

        * Dictionary Schema Details

        * Incremental Configuration

        * Object connections

        * User-defined objects

        * Handler configuration order

        * Access to external objects

        * Access to internal objects

        * Import resolution and custom importers

      * Configuration file format

    * "logging.handlers" --- Logging handlers

      * StreamHandler

      * FileHandler

      * NullHandler

      * WatchedFileHandler

      * BaseRotatingHandler

      * RotatingFileHandler

      * TimedRotatingFileHandler

      * SocketHandler

      * DatagramHandler

      * SysLogHandler

      * NTEventLogHandler

      * SMTPHandler

      * MemoryHandler

      * HTTPHandler

      * QueueHandler

      * QueueListener

    * "getpass" --- Portable password input

    * "curses" --- Terminal handling for character-cell displays

      * Functions

      * Window Objects

      * Constants

    * "curses.textpad" --- Text input widget for curses programs

      * Textbox objects

    * "curses.ascii" --- Utilities for ASCII characters

    * "curses.panel" --- A panel stack extension for curses

      * Functions

      * Panel Objects

    * "platform" ---  Access to underlying platform's identifying data

      * Cross Platform

      * Java Platform

      * Windows Platform

      * macOS Platform

      * Unix Platforms

      * Linux Platforms

    * "errno" --- Standard errno system symbols

    * "ctypes" --- A foreign function library for Python

      * ctypes tutorial

        * Loading dynamic link libraries

        * Accessing functions from loaded dlls

        * Calling functions

        * Fundamental data types

        * Calling functions, continued

        * Calling variadic functions

        * Calling functions with your own custom data types

        * Specifying the required argument types (function prototypes)

        * Return types

        * Passing pointers (or: passing parameters by reference)

        * Structures and unions

        * Structure/union alignment and byte order

        * Bit fields in structures and unions

        * Arrays

        * Pointers

        * Type conversions

        * Incomplete Types

        * Callback functions

        * Accessing values exported from dlls

        * Surprises

        * Variable-sized data types

      * ctypes reference

        * Finding shared libraries

        * Loading shared libraries

        * Foreign functions

        * Function prototypes

        * Utility functions

        * Data types

        * Fundamental data types

        * Structured data types

        * Arrays and pointers

  * Concurrent Execution

    * "threading" --- Thread-based parallelism

      * Thread-Local Data

      * Thread Objects

      * Lock Objects

      * RLock Objects

      * Condition Objects

      * Semaphore Objects

        * "Semaphore" Example

      * Event Objects

      * Timer Objects

      * Barrier Objects

      * Using locks, conditions, and semaphores in the "with"
        statement

    * "multiprocessing" --- Process-based parallelism

      * Introduction

        * The "Process" class

        * Contexts and start methods

        * Exchanging objects between processes

        * Synchronization between processes

        * Sharing state between processes

        * Using a pool of workers

      * Reference

        * "Process" and exceptions

        * Pipes and Queues

        * Miscellaneous

        * Connection Objects

        * Synchronization primitives

        * Shared "ctypes" Objects

          * The "multiprocessing.sharedctypes" module

        * Managers

          * Customized managers

          * Using a remote manager

        * Proxy Objects

          * Cleanup

        * Process Pools

        * Listeners and Clients

          * Address Formats

        * Authentication keys

        * Logging

        * The "multiprocessing.dummy" module

      * Programming guidelines

        * All start methods

        * The *spawn* and *forkserver* start methods

      * Examples

    * "multiprocessing.shared_memory" --- Shared memory for direct
      access across processes

    * The "concurrent" package

    * "concurrent.futures" --- Launching parallel tasks

      * Executor Objects

      * ThreadPoolExecutor

        * ThreadPoolExecutor Example

      * ProcessPoolExecutor

        * ProcessPoolExecutor Example

      * Future Objects

      * Module Functions

      * Exception classes

    * "subprocess" --- Subprocess management

      * Using the "subprocess" Module

        * Frequently Used Arguments

        * Popen Constructor

        * Exceptions

      * Security Considerations

      * Popen Objects

      * Windows Popen Helpers

        * Windows Constants

      * Older high-level API

      * Replacing Older Functions with the "subprocess" Module

        * Replacing **/bin/sh** shell command substitution

        * Replacing shell pipeline

        * Replacing "os.system()"

        * Replacing the "os.spawn" family

        * Replacing "os.popen()", "os.popen2()", "os.popen3()"

        * Replacing functions from the "popen2" module

      * Legacy Shell Invocation Functions

      * Notes

        * Converting an argument sequence to a string on Windows

    * "sched" --- Event scheduler

      * Scheduler Objects

    * "queue" --- A synchronized queue class

      * Queue Objects

      * SimpleQueue Objects

    * "contextvars" --- Context Variables

      * Context Variables

      * Manual Context Management

      * asyncio support

    * "_thread" --- Low-level threading API

  * Networking and Interprocess Communication

    * "asyncio" --- Asynchronous I/O

      * Coroutines and Tasks

        * Coroutines

        * Awaitables

        * Running an asyncio Program

        * Creating Tasks

        * Sleeping

        * Running Tasks Concurrently

        * Shielding From Cancellation

        * Timeouts

        * Waiting Primitives

        * Running in Threads

        * Scheduling From Other Threads

        * Introspection

        * Task Object

        * Generator-based Coroutines

      * Streams

        * StreamReader

        * StreamWriter

        * Examples

          * TCP echo client using streams

          * TCP echo server using streams

          * Get HTTP headers

          * Register an open socket to wait for data using streams

      * Synchronization Primitives

        * Lock

        * Event

        * Condition

        * Semaphore

        * BoundedSemaphore

      * Subprocesses

        * Creating Subprocesses

        * Constants

        * Interacting with Subprocesses

          * Subprocess and Threads

          * Examples

      * Queues

        * Queue

        * Priority Queue

        * LIFO Queue

        * Exceptions

        * Examples

      * Exceptions

      * Event Loop

        * Event Loop Methods

          * Running and stopping the loop

          * Scheduling callbacks

          * Scheduling delayed callbacks

          * Creating Futures and Tasks

          * Opening network connections

          * Creating network servers

          * Transferring files

          * TLS Upgrade

          * Watching file descriptors

          * Working with socket objects directly

          * DNS

          * Working with pipes

          * Unix signals

          * Executing code in thread or process pools

          * Error Handling API

          * Enabling debug mode

          * Running Subprocesses

        * Callback Handles

        * Server Objects

        * Event Loop Implementations

        * Examples

          * Hello World with call_soon()

          * Display the current date with call_later()

          * Watch a file descriptor for read events

          * Set signal handlers for SIGINT and SIGTERM

      * Futures

        * Future Functions

        * Future Object

      * Transports and Protocols

        * Transports

          * Transports Hierarchy

          * Base Transport

          * Read-only Transports

          * Write-only Transports

          * Datagram Transports

          * Subprocess Transports

        * Protocols

          * Base Protocols

          * Base Protocol

          * Streaming Protocols

          * Buffered Streaming Protocols

          * Datagram Protocols

          * Subprocess Protocols

        * Examples

          * TCP Echo Server

          * TCP Echo Client

          * UDP Echo Server

          * UDP Echo Client

          * Connecting Existing Sockets

          * loop.subprocess_exec() and SubprocessProtocol

      * Policies

        * Getting and Setting the Policy

        * Policy Objects

        * Process Watchers

        * Custom Policies

      * Platform Support

        * All Platforms

        * Windows

          * Subprocess Support on Windows

        * macOS

      * High-level API Index

        * Tasks

        * Queues

        * Subprocesses

        * Streams

        * Synchronization

        * Exceptions

      * Low-level API Index

        * Obtaining the Event Loop

        * Event Loop Methods

        * Transports

        * Protocols

        * Event Loop Policies

      * Developing with asyncio

        * Debug Mode

        * Concurrency and Multithreading

        * Running Blocking Code

        * Logging

        * Detect never-awaited coroutines

        * Detect never-retrieved exceptions

    * "socket" --- Low-level networking interface

      * Socket families

      * Module contents

        * Exceptions

        * Constants

        * Functions

          * Creating sockets

          * Other functions

      * Socket Objects

      * Notes on socket timeouts

        * Timeouts and the "connect" method

        * Timeouts and the "accept" method

      * Example

    * "ssl" --- TLS/SSL wrapper for socket objects

      * Functions, Constants, and Exceptions

        * Socket creation

        * Context creation

        * Exceptions

        * Random generation

        * Certificate handling

        * Constants

      * SSL Sockets

      * SSL Contexts

      * Certificates

        * Certificate chains

        * CA certificates

        * Combined key and certificate

        * Self-signed certificates

      * Examples

        * Testing for SSL support

        * Client-side operation

        * Server-side operation

      * Notes on non-blocking sockets

      * Memory BIO Support

      * SSL session

      * Security considerations

        * Best defaults

        * Manual settings

          * Verifying certificates

          * Protocol versions

          * Cipher selection

        * Multi-processing

      * TLS 1.3

    * "select" --- Waiting for I/O completion

      * "/dev/poll" Polling Objects

      * Edge and Level Trigger Polling (epoll) Objects

      * Polling Objects

      * Kqueue Objects

      * Kevent Objects

    * "selectors" --- High-level I/O multiplexing

      * Introduction

      * Classes

      * Examples

    * "signal" --- Set handlers for asynchronous events

      * General rules

        * Execution of Python signal handlers

        * Signals and threads

      * Module contents

      * Example

      * Note on SIGPIPE

      * Note on Signal Handlers and Exceptions

    * "mmap" --- Memory-mapped file support

      * MADV_* Constants

      * MAP_* Constants

  * Internet Data Handling

    * "email" --- An email and MIME handling package

      * "email.message": Representing an email message

      * "email.parser": Parsing email messages

        * FeedParser API

        * Parser API

        * Additional notes

      * "email.generator": Generating MIME documents

      * "email.policy": Policy Objects

      * "email.errors": Exception and Defect classes

      * "email.headerregistry": Custom Header Objects

      * "email.contentmanager": Managing MIME Content

        * Content Manager Instances

      * "email": Examples

      * "email.message.Message": Representing an email message using
        the "compat32" API

      * "email.mime": Creating email and MIME objects from scratch

      * "email.header": Internationalized headers

      * "email.charset": Representing character sets

      * "email.encoders": Encoders

      * "email.utils": Miscellaneous utilities

      * "email.iterators": Iterators

    * "json" --- JSON encoder and decoder

      * Basic Usage

      * Encoders and Decoders

      * Exceptions

      * Standard Compliance and Interoperability

        * Character Encodings

        * Infinite and NaN Number Values

        * Repeated Names Within an Object

        * Top-level Non-Object, Non-Array Values

        * Implementation Limitations

      * Command Line Interface

        * Command line options

    * "mailbox" --- Manipulate mailboxes in various formats

      * "Mailbox" objects

        * "Maildir"

        * "mbox"

        * "MH"

        * "Babyl"

        * "MMDF"

      * "Message" objects

        * "MaildirMessage"

        * "mboxMessage"

        * "MHMessage"

        * "BabylMessage"

        * "MMDFMessage"

      * Exceptions

      * Examples

    * "mimetypes" --- Map filenames to MIME types

      * MimeTypes Objects

    * "base64" --- Base16, Base32, Base64, Base85 Data Encodings

      * Security Considerations

    * "binhex" --- Encode and decode binhex4 files

      * Notes

    * "binascii" --- Convert between binary and ASCII

    * "quopri" --- Encode and decode MIME quoted-printable data

  * Structured Markup Processing Tools

    * "html" --- HyperText Markup Language support

    * "html.parser" --- Simple HTML and XHTML parser

      * Example HTML Parser Application

      * "HTMLParser" Methods

      * Examples

    * "html.entities" --- Definitions of HTML general entities

    * XML Processing Modules

      * XML vulnerabilities

      * The "defusedxml" Package

    * "xml.etree.ElementTree" --- The ElementTree XML API

      * Tutorial

        * XML tree and elements

        * Parsing XML

        * Pull API for non-blocking parsing

        * Finding interesting elements

        * Modifying an XML File

        * Building XML documents

        * Parsing XML with Namespaces

      * XPath support

        * Example

        * Supported XPath syntax

      * Reference

        * Functions

      * XInclude support

        * Example

      * Reference

        * Functions

        * Element Objects

        * ElementTree Objects

        * QName Objects

        * TreeBuilder Objects

        * XMLParser Objects

        * XMLPullParser Objects

        * Exceptions

    * "xml.dom" --- The Document Object Model API

      * Module Contents

      * Objects in the DOM

        * DOMImplementation Objects

        * Node Objects

        * NodeList Objects

        * DocumentType Objects

        * Document Objects

        * Element Objects

        * Attr Objects

        * NamedNodeMap Objects

        * Comment Objects

        * Text and CDATASection Objects

        * ProcessingInstruction Objects

        * Exceptions

      * Conformance

        * Type Mapping

        * Accessor Methods

    * "xml.dom.minidom" --- Minimal DOM implementation

      * DOM Objects

      * DOM Example

      * minidom and the DOM standard

    * "xml.dom.pulldom" --- Support for building partial DOM trees

      * DOMEventStream Objects

    * "xml.sax" --- Support for SAX2 parsers

      * SAXException Objects

    * "xml.sax.handler" --- Base classes for SAX handlers

      * ContentHandler Objects

      * DTDHandler Objects

      * EntityResolver Objects

      * ErrorHandler Objects

      * LexicalHandler Objects

    * "xml.sax.saxutils" --- SAX Utilities

    * "xml.sax.xmlreader" --- Interface for XML parsers

      * XMLReader Objects

      * IncrementalParser Objects

      * Locator Objects

      * InputSource Objects

      * The "Attributes" Interface

      * The "AttributesNS" Interface

    * "xml.parsers.expat" --- Fast XML parsing using Expat

      * XMLParser Objects

      * ExpatError Exceptions

      * Example

      * Content Model Descriptions

      * Expat error constants

  * Internet Protocols and Support

    * "webbrowser" --- Convenient web-browser controller

      * Browser Controller Objects

    * "wsgiref" --- WSGI Utilities and Reference Implementation

      * "wsgiref.util" -- WSGI environment utilities

      * "wsgiref.headers" -- WSGI response header tools

      * "wsgiref.simple_server" -- a simple WSGI HTTP server

      * "wsgiref.validate" --- WSGI conformance checker

      * "wsgiref.handlers" -- server/gateway base classes

      * Examples

    * "urllib" --- URL handling modules

    * "urllib.request" --- Extensible library for opening URLs

      * Request Objects

      * OpenerDirector Objects

      * BaseHandler Objects

      * HTTPRedirectHandler Objects

      * HTTPCookieProcessor Objects

      * ProxyHandler Objects

      * HTTPPasswordMgr Objects

      * HTTPPasswordMgrWithPriorAuth Objects

      * AbstractBasicAuthHandler Objects

      * HTTPBasicAuthHandler Objects

      * ProxyBasicAuthHandler Objects

      * AbstractDigestAuthHandler Objects

      * HTTPDigestAuthHandler Objects

      * ProxyDigestAuthHandler Objects

      * HTTPHandler Objects

      * HTTPSHandler Objects

      * FileHandler Objects

      * DataHandler Objects

      * FTPHandler Objects

      * CacheFTPHandler Objects

      * UnknownHandler Objects

      * HTTPErrorProcessor Objects

      * Examples

      * Legacy interface

      * "urllib.request" Restrictions

    * "urllib.response" --- Response classes used by urllib

    * "urllib.parse" --- Parse URLs into components

      * URL Parsing

      * URL parsing security

      * Parsing ASCII Encoded Bytes

      * Structured Parse Results

      * URL Quoting

    * "urllib.error" --- Exception classes raised by urllib.request

    * "urllib.robotparser" ---  Parser for robots.txt

    * "http" --- HTTP modules

      * HTTP status codes

    * "http.client" --- HTTP protocol client

      * HTTPConnection Objects

      * HTTPResponse Objects

      * Examples

      * HTTPMessage Objects

    * "ftplib" --- FTP protocol client

      * FTP Objects

      * FTP_TLS Objects

    * "poplib" --- POP3 protocol client

      * POP3 Objects

      * POP3 Example

    * "imaplib" --- IMAP4 protocol client

      * IMAP4 Objects

      * IMAP4 Example

    * "smtplib" --- SMTP protocol client

      * SMTP Objects

      * SMTP Example

    * "uuid" --- UUID objects according to **RFC 4122**

      * Example

    * "socketserver" --- A framework for network servers

      * Server Creation Notes

      * Server Objects

      * Request Handler Objects

      * Examples

        * "socketserver.TCPServer" Example

        * "socketserver.UDPServer" Example

        * Asynchronous Mixins

    * "http.server" --- HTTP servers

      * Security Considerations

    * "http.cookies" --- HTTP state management

      * Cookie Objects

      * Morsel Objects

      * Example

    * "http.cookiejar" --- Cookie handling for HTTP clients

      * CookieJar and FileCookieJar Objects

      * FileCookieJar subclasses and co-operation with web browsers

      * CookiePolicy Objects

      * DefaultCookiePolicy Objects

      * Cookie Objects

      * Examples

    * "xmlrpc" --- XMLRPC server and client modules

    * "xmlrpc.client" --- XML-RPC client access

      * ServerProxy Objects

      * DateTime Objects

      * Binary Objects

      * Fault Objects

      * ProtocolError Objects

      * MultiCall Objects

      * Convenience Functions

      * Example of Client Usage

      * Example of Client and Server Usage

    * "xmlrpc.server" --- Basic XML-RPC servers

      * SimpleXMLRPCServer Objects

        * SimpleXMLRPCServer Example

      * CGIXMLRPCRequestHandler

      * Documenting XMLRPC server

      * DocXMLRPCServer Objects

      * DocCGIXMLRPCRequestHandler

    * "ipaddress" --- IPv4/IPv6 manipulation library

      * Convenience factory functions

      * IP Addresses

        * Address objects

        * Conversion to Strings and Integers

        * Operators

          * Comparison operators

          * Arithmetic operators

      * IP Network definitions

        * Prefix, net mask and host mask

        * Network objects

        * Operators

          * Logical operators

          * Iteration

          * Networks as containers of addresses

      * Interface objects

        * Operators

          * Logical operators

      * Other Module Level Functions

      * Custom Exceptions

  * Multimedia Services

    * "wave" --- Read and write WAV files

      * Wave_read Objects

      * Wave_write Objects

    * "colorsys" --- Conversions between color systems

  * Internationalization

    * "gettext" --- Multilingual internationalization services

      * GNU **gettext** API

      * Class-based API

        * The "NullTranslations" class

        * The "GNUTranslations" class

        * Solaris message catalog support

        * The Catalog constructor

      * Internationalizing your programs and modules

        * Localizing your module

        * Localizing your application

        * Changing languages on the fly

        * Deferred translations

      * Acknowledgements

    * "locale" --- Internationalization services

      * Background, details, hints, tips and caveats

      * For extension writers and programs that embed Python

      * Access to message catalogs

  * Program Frameworks

    * "turtle" --- Turtle graphics

      * Introduction

      * Overview of available Turtle and Screen methods

        * Turtle methods

        * Methods of TurtleScreen/Screen

      * Methods of RawTurtle/Turtle and corresponding functions

        * Turtle motion

        * Tell Turtle's state

        * Settings for measurement

        * Pen control

          * Drawing state

          * Color control

          * Filling

          * More drawing control

        * Turtle state

          * Visibility

          * Appearance

        * Using events

        * Special Turtle methods

        * Compound shapes

      * Methods of TurtleScreen/Screen and corresponding functions

        * Window control

        * Animation control

        * Using screen events

        * Input methods

        * Settings and special methods

        * Methods specific to Screen, not inherited from TurtleScreen

      * Public classes

      * Help and configuration

        * How to use help

        * Translation of docstrings into different languages

        * How to configure Screen and Turtles

      * "turtledemo" --- Demo scripts

      * Changes since Python 2.6

      * Changes since Python 3.0

    * "cmd" --- Support for line-oriented command interpreters

      * Cmd Objects

      * Cmd Example

    * "shlex" --- Simple lexical analysis

      * shlex Objects

      * Parsing Rules

      * Improved Compatibility with Shells

  * Graphical User Interfaces with Tk

    * "tkinter" --- Python interface to Tcl/Tk

      * Architecture

      * Tkinter Modules

      * Tkinter Life Preserver

        * A Hello World Program

        * Important Tk Concepts

        * Understanding How Tkinter Wraps Tcl/Tk

        * How do I...? What option does...?

        * Navigating the Tcl/Tk Reference Manual

      * Threading model

      * Handy Reference

        * Setting Options

        * The Packer

        * Packer Options

        * Coupling Widget Variables

        * The Window Manager

        * Tk Option Data Types

        * Bindings and Events

        * The index Parameter

        * Images

      * File Handlers

    * "tkinter.colorchooser" --- Color choosing dialog

    * "tkinter.font" --- Tkinter font wrapper

    * Tkinter Dialogs

      * "tkinter.simpledialog" --- Standard Tkinter input dialogs

      * "tkinter.filedialog" --- File selection dialogs

        * Native Load/Save Dialogs

      * "tkinter.commondialog" --- Dialog window templates

    * "tkinter.messagebox" --- Tkinter message prompts

    * "tkinter.scrolledtext" --- Scrolled Text Widget

    * "tkinter.dnd" --- Drag and drop support

    * "tkinter.ttk" --- Tk themed widgets

      * Using Ttk

      * Ttk Widgets

      * Widget

        * Standard Options

        * Scrollable Widget Options

        * Label Options

        * Compatibility Options

        * Widget States

        * ttk.Widget

      * Combobox

        * Options

        * Virtual events

        * ttk.Combobox

      * Spinbox

        * Options

        * Virtual events

        * ttk.Spinbox

      * Notebook

        * Options

        * Tab Options

        * Tab Identifiers

        * Virtual Events

        * ttk.Notebook

      * Progressbar

        * Options

        * ttk.Progressbar

      * Separator

        * Options

      * Sizegrip

        * Platform-specific notes

        * Bugs

      * Treeview

        * Options

        * Item Options

        * Tag Options

        * Column Identifiers

        * Virtual Events

        * ttk.Treeview

      * Ttk Styling

        * Layouts

    * "tkinter.tix" --- Extension widgets for Tk

      * Using Tix

      * Tix Widgets

        * Basic Widgets

        * File Selectors

        * Hierarchical ListBox

        * Tabular ListBox

        * Manager Widgets

        * Image Types

        * Miscellaneous Widgets

        * Form Geometry Manager

      * Tix Commands

    * IDLE

      * Menus

        * File menu (Shell and Editor)

        * Edit menu (Shell and Editor)

        * Format menu (Editor window only)

        * Run menu (Editor window only)

        * Shell menu (Shell window only)

        * Debug menu (Shell window only)

        * Options menu (Shell and Editor)

        * Window menu (Shell and Editor)

        * Help menu (Shell and Editor)

        * Context menus

      * Editing and Navigation

        * Editor windows

        * Key bindings

        * Automatic indentation

        * Search and Replace

        * Completions

        * Calltips

        * Code Context

        * Shell window

        * Text colors

      * Startup and Code Execution

        * Command line usage

        * Startup failure

        * Running user code

        * User output in Shell

        * Developing tkinter applications

        * Running without a subprocess

      * Help and Preferences

        * Help sources

        * Setting preferences

        * IDLE on macOS

        * Extensions

      * idlelib

  * Development Tools

    * "typing" --- Support for type hints

      * Relevant PEPs

      * Type aliases

      * NewType

      * Callable

      * Generics

      * User-defined generic types

      * The "Any" type

      * Nominal vs structural subtyping

      * Module contents

        * Special typing primitives

          * Special types

          * Special forms

          * Building generic types

          * Other special directives

        * Generic concrete collections

          * Corresponding to built-in types

          * Corresponding to types in "collections"

          * Other concrete types

        * Abstract Base Classes

          * Corresponding to collections in "collections.abc"

          * Corresponding to other types in "collections.abc"

          * Asynchronous programming

          * Context manager types

        * Protocols

        * Functions and decorators

        * Introspection helpers

        * Constant

    * "pydoc" --- Documentation generator and online help system

    * Python Development Mode

    * Effects of the Python Development Mode

    * ResourceWarning Example

    * Bad file descriptor error example

    * "doctest" --- Test interactive Python examples

      * Simple Usage: Checking Examples in Docstrings

      * Simple Usage: Checking Examples in a Text File

      * How It Works

        * Which Docstrings Are Examined?

        * How are Docstring Examples Recognized?

        * What's the Execution Context?

        * What About Exceptions?

        * Option Flags

        * Directives

        * Warnings

      * Basic API

      * Unittest API

      * Advanced API

        * DocTest Objects

        * Example Objects

        * DocTestFinder objects

        * DocTestParser objects

        * DocTestRunner objects

        * OutputChecker objects

      * Debugging

      * Soapbox

    * "unittest" --- Unit testing framework

      * Basic example

      * Command-Line Interface

        * Command-line options

      * Test Discovery

      * Organizing test code

      * Re-using old test code

      * Skipping tests and expected failures

      * Distinguishing test iterations using subtests

      * Classes and functions

        * Test cases

          * Deprecated aliases

        * Grouping tests

        * Loading and running tests

          * load_tests Protocol

      * Class and Module Fixtures

        * setUpClass and tearDownClass

        * setUpModule and tearDownModule

      * Signal Handling

    * "unittest.mock" --- mock object library

      * Quick Guide

      * The Mock Class

        * Calling

        * Deleting Attributes

        * Mock names and the name attribute

        * Attaching Mocks as Attributes

      * The patchers

        * patch

        * patch.object

        * patch.dict

        * patch.multiple

        * patch methods: start and stop

        * patch builtins

        * TEST_PREFIX

        * Nesting Patch Decorators

        * Where to patch

        * Patching Descriptors and Proxy Objects

      * MagicMock and magic method support

        * Mocking Magic Methods

        * Magic Mock

      * Helpers

        * sentinel

        * DEFAULT

        * call

        * create_autospec

        * ANY

        * FILTER_DIR

        * mock_open

        * Autospeccing

        * Sealing mocks

    * "unittest.mock" --- getting started

      * Using Mock

        * Mock Patching Methods

        * Mock for Method Calls on an Object

        * Mocking Classes

        * Naming your mocks

        * Tracking all Calls

        * Setting Return Values and Attributes

        * Raising exceptions with mocks

        * Side effect functions and iterables

        * Mocking asynchronous iterators

        * Mocking asynchronous context manager

        * Creating a Mock from an Existing Object

      * Patch Decorators

      * Further Examples

        * Mocking chained calls

        * Partial mocking

        * Mocking a Generator Method

        * Applying the same patch to every test method

        * Mocking Unbound Methods

        * Checking multiple calls with mock

        * Coping with mutable arguments

        * Nesting Patches

        * Mocking a dictionary with MagicMock

        * Mock subclasses and their attributes

        * Mocking imports with patch.dict

        * Tracking order of calls and less verbose call assertions

        * More complex argument matching

    * 2to3 --- Automated Python 2 to 3 code translation

      * Using 2to3

      * Fixers

      * "lib2to3" --- 2to3's library

    * "test" --- Regression tests package for Python

      * Writing Unit Tests for the "test" package

      * Running tests using the command-line interface

    * "test.support" --- Utilities for the Python test suite

    * "test.support.socket_helper" --- Utilities for socket tests

    * "test.support.script_helper" --- Utilities for the Python
      execution tests

    * "test.support.bytecode_helper" --- Support tools for testing
      correct bytecode generation

    * "test.support.threading_helper" --- Utilities for threading
      tests

    * "test.support.os_helper" --- Utilities for os tests

    * "test.support.import_helper" --- Utilities for import tests

    * "test.support.warnings_helper" --- Utilities for warnings tests

  * Debugging and Profiling

    * Audit events table

    * "bdb" --- Debugger framework

    * "faulthandler" --- Dump the Python traceback

      * Dumping the traceback

      * Fault handler state

      * Dumping the tracebacks after a timeout

      * Dumping the traceback on a user signal

      * Issue with file descriptors

      * Example

    * "pdb" --- The Python Debugger

      * Debugger Commands

    * The Python Profilers

      * Introduction to the profilers

      * Instant User's Manual

      * "profile" and "cProfile" Module Reference

      * The "Stats" Class

      * What Is Deterministic Profiling?

      * Limitations

      * Calibration

      * Using a custom timer

    * "timeit" --- Measure execution time of small code snippets

      * Basic Examples

      * Python Interface

      * Command-Line Interface

      * Examples

    * "trace" --- Trace or track Python statement execution

      * Command-Line Usage

        * Main options

        * Modifiers

        * Filters

      * Programmatic Interface

    * "tracemalloc" --- Trace memory allocations

      * Examples

        * Display the top 10

        * Compute differences

        * Get the traceback of a memory block

        * Pretty top

          * Record the current and peak size of all traced memory
            blocks

      * API

        * Functions

        * DomainFilter

        * Filter

        * Frame

        * Snapshot

        * Statistic

        * StatisticDiff

        * Trace

        * Traceback

  * Software Packaging and Distribution

    * "distutils" --- Building and installing Python modules

    * "ensurepip" --- Bootstrapping the "pip" installer

      * Command line interface

      * Module API

    * "venv" --- Creation of virtual environments

      * Creating virtual environments

      * How venvs work

      * API

      * An example of extending "EnvBuilder"

    * "zipapp" --- Manage executable Python zip archives

      * Basic Example

      * Command-Line Interface

      * Python API

      * Examples

      * Specifying the Interpreter

      * Creating Standalone Applications with zipapp

        * Making a Windows executable

        * Caveats

      * The Python Zip Application Archive Format

  * Python Runtime Services

    * "sys" --- System-specific parameters and functions

    * "sysconfig" --- Provide access to Python's configuration
      information

      * Configuration variables

      * Installation paths

      * Other functions

      * Using "sysconfig" as a script

    * "builtins" --- Built-in objects

    * "__main__" --- Top-level code environment

      * "__name__ == '__main__'"

        * What is the "top-level code environment"?

        * Idiomatic Usage

        * Packaging Considerations

      * "__main__.py" in Python Packages

        * Idiomatic Usage

      * "import __main__"

    * "warnings" --- Warning control

      * Warning Categories

      * The Warnings Filter

        * Describing Warning Filters

        * Default Warning Filter

        * Overriding the default filter

      * Temporarily Suppressing Warnings

      * Testing Warnings

      * Updating Code For New Versions of Dependencies

      * Available Functions

      * Available Context Managers

    * "dataclasses" --- Data Classes

      * Module contents

      * Post-init processing

      * Class variables

      * Init-only variables

      * Frozen instances

      * Inheritance

      * Re-ordering of keyword-only parameters in "__init__()"

      * Default factory functions

      * Mutable default values

      * Descriptor-typed fields

    * "contextlib" --- Utilities for "with"-statement contexts

      * Utilities

      * Examples and Recipes

        * Supporting a variable number of context managers

        * Catching exceptions from "__enter__" methods

        * Cleaning up in an "__enter__" implementation

        * Replacing any use of "try-finally" and flag variables

        * Using a context manager as a function decorator

      * Single use, reusable and reentrant context managers

        * Reentrant context managers

        * Reusable context managers

    * "abc" --- Abstract Base Classes

    * "atexit" --- Exit handlers

      * "atexit" Example

    * "traceback" --- Print or retrieve a stack traceback

      * "TracebackException" Objects

      * "StackSummary" Objects

      * "FrameSummary" Objects

      * Traceback Examples

    * "__future__" --- Future statement definitions

    * "gc" --- Garbage Collector interface

    * "inspect" --- Inspect live objects

      * Types and members

      * Retrieving source code

      * Introspecting callables with the Signature object

      * Classes and functions

      * The interpreter stack

      * Fetching attributes statically

      * Current State of Generators and Coroutines

      * Code Objects Bit Flags

      * Command Line Interface

    * "site" --- Site-specific configuration hook

      * Readline configuration

      * Module contents

      * Command Line Interface

  * Custom Python Interpreters

    * "code" --- Interpreter base classes

      * Interactive Interpreter Objects

      * Interactive Console Objects

    * "codeop" --- Compile Python code

  * Importing Modules

    * "zipimport" --- Import modules from Zip archives

      * zipimporter Objects

      * Examples

    * "pkgutil" --- Package extension utility

    * "modulefinder" --- Find modules used by a script

      * Example usage of "ModuleFinder"

    * "runpy" --- Locating and executing Python modules

    * "importlib" --- The implementation of "import"

      * Introduction

      * Functions

      * "importlib.abc" -- Abstract base classes related to import

      * "importlib.resources" -- Resources

      * "importlib.machinery" -- Importers and path hooks

      * "importlib.util" -- Utility code for importers

      * Examples

        * Importing programmatically

        * Checking if a module can be imported

        * Importing a source file directly

        * Implementing lazy imports

        * Setting up an importer

        * Approximating "importlib.import_module()"

    * Using "importlib.metadata"

      * Overview

      * Functional API

        * Entry points

        * Distribution metadata

        * Distribution versions

        * Distribution files

        * Distribution requirements

        * Package distributions

      * Distributions

      * Extending the search algorithm

  * Python Language Services

    * "ast" --- Abstract Syntax Trees

      * Abstract Grammar

      * Node classes

        * Literals

        * Variables

        * Expressions

          * Subscripting

          * Comprehensions

        * Statements

          * Imports

        * Control flow

        * Pattern matching

        * Function and class definitions

        * Async and await

      * "ast" Helpers

      * Compiler Flags

      * Command-Line Usage

    * "symtable" --- Access to the compiler's symbol tables

      * Generating Symbol Tables

      * Examining Symbol Tables

    * "token" --- Constants used with Python parse trees

    * "keyword" --- Testing for Python keywords

    * "tokenize" --- Tokenizer for Python source

      * Tokenizing Input

      * Command-Line Usage

      * Examples

    * "tabnanny" --- Detection of ambiguous indentation

    * "pyclbr" --- Python module browser support

      * Function Objects

      * Class Objects

    * "py_compile" --- Compile Python source files

      * Command-Line Interface

    * "compileall" --- Byte-compile Python libraries

      * Command-line use

      * Public functions

    * "dis" --- Disassembler for Python bytecode

      * Bytecode analysis

      * Analysis functions

      * Python Bytecode Instructions

      * Opcode collections

    * "pickletools" --- Tools for pickle developers

      * Command line usage

        * Command line options

      * Programmatic Interface

  * MS Windows Specific Services

    * "msvcrt" --- Useful routines from the MS VC++ runtime

      * File Operations

      * Console I/O

      * Other Functions

    * "winreg" --- Windows registry access

      * Functions

      * Constants

        * HKEY_* Constants

        * Access Rights

          * 64-bit Specific

        * Value Types

      * Registry Handle Objects

    * "winsound" --- Sound-playing interface for Windows

  * Unix Specific Services

    * "posix" --- The most common POSIX system calls

      * Large File Support

      * Notable Module Contents

    * "pwd" --- The password database

    * "grp" --- The group database

    * "termios" --- POSIX style tty control

      * Example

    * "tty" --- Terminal control functions

    * "pty" --- Pseudo-terminal utilities

      * Example

    * "fcntl" --- The "fcntl" and "ioctl" system calls

    * "resource" --- Resource usage information

      * Resource Limits

      * Resource Usage

    * "syslog" --- Unix syslog library routines

      * Examples

        * Simple example

  * Superseded Modules

    * "aifc" --- Read and write AIFF and AIFC files

    * "asynchat" --- Asynchronous socket command/response handler

      * asynchat Example

    * "asyncore" --- Asynchronous socket handler

      * asyncore Example basic HTTP client

      * asyncore Example basic echo server

    * "audioop" --- Manipulate raw audio data

    * "cgi" --- Common Gateway Interface support

      * Introduction

      * Using the cgi module

      * Higher Level Interface

      * Functions

      * Caring about security

      * Installing your CGI script on a Unix system

      * Testing your CGI script

      * Debugging CGI scripts

      * Common problems and solutions

    * "cgitb" --- Traceback manager for CGI scripts

    * "chunk" --- Read IFF chunked data

    * "crypt" --- Function to check Unix passwords

      * Hashing Methods

      * Module Attributes

      * Module Functions

      * Examples

    * "imghdr" --- Determine the type of an image

    * "imp" --- Access the *import* internals

      * Examples

    * "mailcap" --- Mailcap file handling

    * "msilib" --- Read and write Microsoft Installer files

      * Database Objects

      * View Objects

      * Summary Information Objects

      * Record Objects

      * Errors

      * CAB Objects

      * Directory Objects

      * Features

      * GUI classes

      * Precomputed tables

    * "nis" --- Interface to Sun's NIS (Yellow Pages)

    * "nntplib" --- NNTP protocol client

      * NNTP Objects

        * Attributes

        * Methods

      * Utility functions

    * "optparse" --- Parser for command line options

      * Background

        * Terminology

        * What are options for?

        * What are positional arguments for?

      * Tutorial

        * Understanding option actions

        * The store action

        * Handling boolean (flag) options

        * Other actions

        * Default values

        * Generating help

          * Grouping Options

        * Printing a version string

        * How "optparse" handles errors

        * Putting it all together

      * Reference Guide

        * Creating the parser

        * Populating the parser

        * Defining options

        * Option attributes

        * Standard option actions

        * Standard option types

        * Parsing arguments

        * Querying and manipulating your option parser

        * Conflicts between options

        * Cleanup

        * Other methods

      * Option Callbacks

        * Defining a callback option

        * How callbacks are called

        * Raising errors in a callback

        * Callback example 1: trivial callback

        * Callback example 2: check option order

        * Callback example 3: check option order (generalized)

        * Callback example 4: check arbitrary condition

        * Callback example 5: fixed arguments

        * Callback example 6: variable arguments

      * Extending "optparse"

        * Adding new types

        * Adding new actions

    * "ossaudiodev" --- Access to OSS-compatible audio devices

      * Audio Device Objects

      * Mixer Device Objects

    * "pipes" --- Interface to shell pipelines

      * Template Objects

    * "smtpd" --- SMTP Server

      * SMTPServer Objects

      * DebuggingServer Objects

      * PureProxy Objects

      * MailmanProxy Objects

      * SMTPChannel Objects

    * "sndhdr" --- Determine type of sound file

    * "spwd" --- The shadow password database

    * "sunau" --- Read and write Sun AU files

      * AU_read Objects

      * AU_write Objects

    * "telnetlib" --- Telnet client

      * Telnet Objects

      * Telnet Example

    * "uu" --- Encode and decode uuencode files

    * "xdrlib" --- Encode and decode XDR data

      * Packer Objects

      * Unpacker Objects

      * Exceptions

  * Security Considerations

* Extending and Embedding the Python Interpreter

  * Recommended third party tools

  * Creating extensions without third party tools

    * 1. Extending Python with C or C++

      * 1.1. A Simple Example

      * 1.2. Intermezzo: Errors and Exceptions

      * 1.3. Back to the Example

      * 1.4. The Module's Method Table and Initialization Function

      * 1.5. Compilation and Linkage

      * 1.6. Calling Python Functions from C

      * 1.7. Extracting Parameters in Extension Functions

      * 1.8. Keyword Parameters for Extension Functions

      * 1.9. Building Arbitrary Values

      * 1.10. Reference Counts

        * 1.10.1. Reference Counting in Python

        * 1.10.2. Ownership Rules

        * 1.10.3. Thin Ice

        * 1.10.4. NULL Pointers

      * 1.11. Writing Extensions in C++

      * 1.12. Providing a C API for an Extension Module

    * 2. Defining Extension Types: Tutorial

      * 2.1. The Basics

      * 2.2. Adding data and methods to the Basic example

      * 2.3. Providing finer control over data attributes

      * 2.4. Supporting cyclic garbage collection

      * 2.5. Subclassing other types

    * 3. Defining Extension Types: Assorted Topics

      * 3.1. Finalization and De-allocation

      * 3.2. Object Presentation

      * 3.3. Attribute Management

        * 3.3.1. Generic Attribute Management

        * 3.3.2. Type-specific Attribute Management

      * 3.4. Object Comparison

      * 3.5. Abstract Protocol Support

      * 3.6. Weak Reference Support

      * 3.7. More Suggestions

    * 4. Building C and C++ Extensions

      * 4.1. Building C and C++ Extensions with distutils

      * 4.2. Distributing your extension modules

    * 5. Building C and C++ Extensions on Windows

      * 5.1. A Cookbook Approach

      * 5.2. Differences Between Unix and Windows

      * 5.3. Using DLLs in Practice

  * Embedding the CPython runtime in a larger application

    * 1. Embedding Python in Another Application

      * 1.1. Very High Level Embedding

      * 1.2. Beyond Very High Level Embedding: An overview

      * 1.3. Pure Embedding

      * 1.4. Extending Embedded Python

      * 1.5. Embedding Python in C++

      * 1.6. Compiling and Linking under Unix-like systems

* Python/C API Reference Manual

  * Introduction

    * Coding standards

    * Include Files

    * Useful macros

    * Objects, Types and Reference Counts

      * Reference Counts

        * Reference Count Details

      * Types

    * Exceptions

    * Embedding Python

    * Debugging Builds

  * C API Stability

    * Stable Application Binary Interface

      * Limited API Scope and Performance

      * Limited API Caveats

    * Platform Considerations

    * Contents of Limited API

  * The Very High Level Layer

  * Reference Counting

  * Exception Handling

    * Printing and clearing

    * Raising exceptions

    * Issuing warnings

    * Querying the error indicator

    * Signal Handling

    * Exception Classes

    * Exception Objects

    * Unicode Exception Objects

    * Recursion Control

    * Standard Exceptions

    * Standard Warning Categories

  * Utilities

    * Operating System Utilities

    * System Functions

    * Process Control

    * Importing Modules

    * Data marshalling support

    * Parsing arguments and building values

      * Parsing arguments

        * Strings and buffers

        * Numbers

        * Other objects

        * API Functions

      * Building values

    * String conversion and formatting

    * Reflection

    * Codec registry and support functions

      * Codec lookup API

      * Registry API for Unicode encoding error handlers

  * Abstract Objects Layer

    * Object Protocol

    * Call Protocol

      * The *tp_call* Protocol

      * The Vectorcall Protocol

        * Recursion Control

        * Vectorcall Support API

      * Object Calling API

      * Call Support API

    * Number Protocol

    * Sequence Protocol

    * Mapping Protocol

    * Iterator Protocol

    * Buffer Protocol

      * Buffer structure

      * Buffer request types

        * request-independent fields

        * readonly, format

        * shape, strides, suboffsets

        * contiguity requests

        * compound requests

      * Complex arrays

        * NumPy-style: shape and strides

        * PIL-style: shape, strides and suboffsets

      * Buffer-related functions

    * Old Buffer Protocol

  * Concrete Objects Layer

    * Fundamental Objects

      * Type Objects

        * Creating Heap-Allocated Types

      * The "None" Object

    * Numeric Objects

      * Integer Objects

      * Boolean Objects

      * Floating Point Objects

      * Complex Number Objects

        * Complex Numbers as C Structures

        * Complex Numbers as Python Objects

    * Sequence Objects

      * Bytes Objects

      * Byte Array Objects

        * Type check macros

        * Direct API functions

        * Macros

      * Unicode Objects and Codecs

        * Unicode Objects

          * Unicode Type

          * Unicode Character Properties

          * Creating and accessing Unicode strings

          * Deprecated Py_UNICODE APIs

          * Locale Encoding

          * File System Encoding

          * wchar_t Support

        * Built-in Codecs

          * Generic Codecs

          * UTF-8 Codecs

          * UTF-32 Codecs

          * UTF-16 Codecs

          * UTF-7 Codecs

          * Unicode-Escape Codecs

          * Raw-Unicode-Escape Codecs

          * Latin-1 Codecs

          * ASCII Codecs

          * Character Map Codecs

          * MBCS codecs for Windows

          * Methods & Slots

        * Methods and Slot Functions

      * Tuple Objects

      * Struct Sequence Objects

      * List Objects

    * Container Objects

      * Dictionary Objects

      * Set Objects

    * Function Objects

      * Function Objects

      * Instance Method Objects

      * Method Objects

      * Cell Objects

      * Code Objects

    * Other Objects

      * File Objects

      * Module Objects

        * Initializing C modules

          * Single-phase initialization

          * Multi-phase initialization

          * Low-level module creation functions

          * Support functions

        * Module lookup

      * Iterator Objects

      * Descriptor Objects

      * Slice Objects

      * Ellipsis Object

      * MemoryView objects

      * Weak Reference Objects

      * Capsules

      * Generator Objects

      * Coroutine Objects

      * Context Variables Objects

      * DateTime Objects

      * Objects for Type Hinting

  * Initialization, Finalization, and Threads

    * Before Python Initialization

    * Global configuration variables

    * Initializing and finalizing the interpreter

    * Process-wide parameters

    * Thread State and the Global Interpreter Lock

      * Releasing the GIL from extension code

      * Non-Python created threads

      * Cautions about fork()

      * High-level API

      * Low-level API

    * Sub-interpreter support

      * Bugs and caveats

    * Asynchronous Notifications

    * Profiling and Tracing

    * Advanced Debugger Support

    * Thread Local Storage Support

      * Thread Specific Storage (TSS) API

        * Dynamic Allocation

        * Methods

      * Thread Local Storage (TLS) API

  * Python Initialization Configuration

    * Example

    * PyWideStringList

    * PyStatus

    * PyPreConfig

    * Preinitialize Python with PyPreConfig

    * PyConfig

    * Initialization with PyConfig

    * Isolated Configuration

    * Python Configuration

    * Python Path Configuration

    * Py_RunMain()

    * Py_GetArgcArgv()

    * Multi-Phase Initialization Private Provisional API

  * Memory Management

    * Overview

    * Allocator Domains

    * Raw Memory Interface

    * Memory Interface

    * Object allocators

    * Default Memory Allocators

    * Customize Memory Allocators

    * Debug hooks on the Python memory allocators

    * The pymalloc allocator

      * Customize pymalloc Arena Allocator

    * tracemalloc C API

    * Examples

  * Object Implementation Support

    * Allocating Objects on the Heap

    * Common Object Structures

      * Base object types and macros

      * Implementing functions and methods

      * Accessing attributes of extension types

    * Type Objects

      * Quick Reference

        * "tp slots"

        * sub-slots

        * slot typedefs

      * PyTypeObject Definition

      * PyObject Slots

      * PyVarObject Slots

      * PyTypeObject Slots

      * Static Types

      * Heap Types

    * Number Object Structures

    * Mapping Object Structures

    * Sequence Object Structures

    * Buffer Object Structures

    * Async Object Structures

    * Slot Type typedefs

    * Examples

    * Supporting Cyclic Garbage Collection

      * Controlling the Garbage Collector State

  * API and ABI Versioning

* Distributing Python Modules

  * Key terms

  * Open source licensing and collaboration

  * Installing the tools

  * Reading the Python Packaging User Guide

  * How do I...?

    * ... choose a name for my project?

    * ... create and distribute binary extensions?

* Installing Python Modules

  * Key terms

  * Basic usage

  * How do I ...?

    * ... install "pip" in versions of Python prior to Python 3.4?

    * ... install packages just for the current user?

    * ... install scientific Python packages?

    * ... work with multiple versions of Python installed in parallel?

  * Common installation issues

    * Installing into the system Python on Linux

    * Pip not installed

    * Installing binary extensions

* Python HOWTOs

  * Porting Python 2 Code to Python 3

    * The Short Explanation

    * Details

      * Drop support for Python 2.6 and older

      * Make sure you specify the proper version support in your
        "setup.py" file

      * Have good test coverage

      * Learn the differences between Python 2 & 3

      * Update your code

        * Division

        * Text versus binary data

        * Use feature detection instead of version detection

      * Prevent compatibility regressions

      * Check which dependencies block your transition

      * Update your "setup.py" file to denote Python 3 compatibility

      * Use continuous integration to stay compatible

      * Consider using optional static type checking

  * Porting Extension Modules to Python 3

  * Curses Programming with Python

    * What is curses?

      * The Python curses module

    * Starting and ending a curses application

    * Windows and Pads

    * Displaying Text

      * Attributes and Color

    * User Input

    * For More Information

  * Descriptor HowTo Guide

    * Primer

      * Simple example: A descriptor that returns a constant

      * Dynamic lookups

      * Managed attributes

      * Customized names

      * Closing thoughts

    * Complete Practical Example

      * Validator class

      * Custom validators

      * Practical application

    * Technical Tutorial

      * Abstract

      * Definition and introduction

      * Descriptor protocol

      * Overview of descriptor invocation

      * Invocation from an instance

      * Invocation from a class

      * Invocation from super

      * Summary of invocation logic

      * Automatic name notification

      * ORM example

    * Pure Python Equivalents

      * Properties

      * Functions and methods

      * Kinds of methods

      * Static methods

      * Class methods

      * Member objects and __slots__

  * Functional Programming HOWTO

    * Introduction

      * Formal provability

      * Modularity

      * Ease of debugging and testing

      * Composability

    * Iterators

      * Data Types That Support Iterators

    * Generator expressions and list comprehensions

    * Generators

      * Passing values into a generator

    * Built-in functions

    * The itertools module

      * Creating new iterators

      * Calling functions on elements

      * Selecting elements

      * Combinatoric functions

      * Grouping elements

    * The functools module

      * The operator module

    * Small functions and the lambda expression

    * Revision History and Acknowledgements

    * References

      * General

      * Python-specific

      * Python documentation

  * Logging HOWTO

    * Basic Logging Tutorial

      * When to use logging

      * A simple example

      * Logging to a file

      * Logging from multiple modules

      * Logging variable data

      * Changing the format of displayed messages

      * Displaying the date/time in messages

      * Next Steps

    * Advanced Logging Tutorial

      * Logging Flow

      * Loggers

      * Handlers

      * Formatters

      * Configuring Logging

      * What happens if no configuration is provided

      * Configuring Logging for a Library

    * Logging Levels

      * Custom Levels

    * Useful Handlers

    * Exceptions raised during logging

    * Using arbitrary objects as messages

    * Optimization

  * Logging Cookbook

    * Using logging in multiple modules

    * Logging from multiple threads

    * Multiple handlers and formatters

    * Logging to multiple destinations

    * Custom handling of levels

    * Configuration server example

    * Dealing with handlers that block

    * Sending and receiving logging events across a network

      * Running a logging socket listener in production

    * Adding contextual information to your logging output

      * Using LoggerAdapters to impart contextual information

        * Using objects other than dicts to pass contextual
          information

      * Using Filters to impart contextual information

    * Use of "contextvars"

    * Imparting contextual information in handlers

    * Logging to a single file from multiple processes

      * Using concurrent.futures.ProcessPoolExecutor

      * Deploying Web applications using Gunicorn and uWSGI

    * Using file rotation

    * Use of alternative formatting styles

    * Customizing "LogRecord"

    * Subclassing QueueHandler - a ZeroMQ example

    * Subclassing QueueListener - a ZeroMQ example

    * An example dictionary-based configuration

    * Using a rotator and namer to customize log rotation processing

    * A more elaborate multiprocessing example

    * Inserting a BOM into messages sent to a SysLogHandler

    * Implementing structured logging

    * Customizing handlers with "dictConfig()"

    * Using particular formatting styles throughout your application

      * Using LogRecord factories

      * Using custom message objects

    * Configuring filters with "dictConfig()"

    * Customized exception formatting

    * Speaking logging messages

    * Buffering logging messages and outputting them conditionally

    * Sending logging messages to email, with buffering

    * Formatting times using UTC (GMT) via configuration

    * Using a context manager for selective logging

    * A CLI application starter template

    * A Qt GUI for logging

    * Logging to syslog with RFC5424 support

    * How to treat a logger like an output stream

    * Patterns to avoid

      * Opening the same log file multiple times

      * Using loggers as attributes in a class or passing them as
        parameters

      * Adding handlers other than "NullHandler" to a logger in a
        library

      * Creating a lot of loggers

    * Other resources

  * Regular Expression HOWTO

    * Introduction

    * Simple Patterns

      * Matching Characters

      * Repeating Things

    * Using Regular Expressions

      * Compiling Regular Expressions

      * The Backslash Plague

      * Performing Matches

      * Module-Level Functions

      * Compilation Flags

    * More Pattern Power

      * More Metacharacters

      * Grouping

      * Non-capturing and Named Groups

      * Lookahead Assertions

    * Modifying Strings

      * Splitting Strings

      * Search and Replace

    * Common Problems

      * Use String Methods

      * match() versus search()

      * Greedy versus Non-Greedy

      * Using re.VERBOSE

    * Feedback

  * Socket Programming HOWTO

    * Sockets

      * History

    * Creating a Socket

      * IPC

    * Using a Socket

      * Binary Data

    * Disconnecting

      * When Sockets Die

    * Non-blocking Sockets

  * Sorting HOW TO

    * Sorting Basics

    * Key Functions

    * Operator Module Functions

    * Ascending and Descending

    * Sort Stability and Complex Sorts

    * The Old Way Using Decorate-Sort-Undecorate

    * The Old Way Using the *cmp* Parameter

    * Odd and Ends

  * Unicode HOWTO

    * Introduction to Unicode

      * Definitions

      * Encodings

      * References

    * Python's Unicode Support

      * The String Type

      * Converting to Bytes

      * Unicode Literals in Python Source Code

      * Unicode Properties

      * Comparing Strings

      * Unicode Regular Expressions

      * References

    * Reading and Writing Unicode Data

      * Unicode filenames

      * Tips for Writing Unicode-aware Programs

        * Converting Between File Encodings

        * Files in an Unknown Encoding

      * References

    * Acknowledgements

  * HOWTO Fetch Internet Resources Using The urllib Package

    * Introduction

    * Fetching URLs

      * Data

      * Headers

    * Handling Exceptions

      * URLError

      * HTTPError

        * Error Codes

      * Wrapping it Up

        * Number 1

        * Number 2

    * info and geturl

    * Openers and Handlers

    * Basic Authentication

    * Proxies

    * Sockets and Layers

    * Footnotes

  * Argparse Tutorial

    * Concepts

    * The basics

    * Introducing Positional arguments

    * Introducing Optional arguments

      * Short options

    * Combining Positional and Optional arguments

    * Getting a little more advanced

      * Conflicting options

    * Conclusion

  * An introduction to the ipaddress module

    * Creating Address/Network/Interface objects

      * A Note on IP Versions

      * IP Host Addresses

      * Defining Networks

      * Host Interfaces

    * Inspecting Address/Network/Interface Objects

    * Networks as lists of Addresses

    * Comparisons

    * Using IP Addresses with other modules

    * Getting more detail when instance creation fails

  * Argument Clinic How-To

    * The Goals Of Argument Clinic

    * Basic Concepts And Usage

    * Converting Your First Function

    * Advanced Topics

      * Symbolic default values

      * Renaming the C functions and variables generated by Argument
        Clinic

      * Converting functions using PyArg_UnpackTuple

      * Optional Groups

      * Using real Argument Clinic converters, instead of "legacy
        converters"

      * Py_buffer

      * Advanced converters

      * Parameter default values

      * The "NULL" default value

      * Expressions specified as default values

      * Using a return converter

      * Cloning existing functions

      * Calling Python code

      * Using a "self converter"

      * Using a "defining class" converter

      * Writing a custom converter

      * Writing a custom return converter

      * METH_O and METH_NOARGS

      * tp_new and tp_init functions

      * Changing and redirecting Clinic's output

      * The #ifdef trick

      * Using Argument Clinic in Python files

  * Instrumenting CPython with DTrace and SystemTap

    * Enabling the static markers

    * Static DTrace probes

    * Static SystemTap markers

    * Available static markers

    * SystemTap Tapsets

    * Examples

  * Annotations Best Practices

    * Accessing The Annotations Dict Of An Object In Python 3.10 And
      Newer

    * Accessing The Annotations Dict Of An Object In Python 3.9 And
      Older

    * Manually Un-Stringizing Stringized Annotations

    * Best Practices For "__annotations__" In Any Python Version

    * "__annotations__" Quirks

* Python Frequently Asked Questions

  * General Python FAQ

    * General Information

    * Python in the real world

  * Programming FAQ

    * General Questions

    * Core Language

    * Numbers and strings

    * Performance

    * Sequences (Tuples/Lists)

    * Objects

    * Modules

  * Design and History FAQ

    * Why does Python use indentation for grouping of statements?

    * Why am I getting strange results with simple arithmetic
      operations?

    * Why are floating-point calculations so inaccurate?

    * Why are Python strings immutable?

    * Why must 'self' be used explicitly in method definitions and
      calls?

    * Why can't I use an assignment in an expression?

    * Why does Python use methods for some functionality (e.g.
      list.index()) but functions for other (e.g. len(list))?

    * Why is join() a string method instead of a list or tuple method?

    * How fast are exceptions?

    * Why isn't there a switch or case statement in Python?

    * Can't you emulate threads in the interpreter instead of relying
      on an OS-specific thread implementation?

    * Why can't lambda expressions contain statements?

    * Can Python be compiled to machine code, C or some other
      language?

    * How does Python manage memory?

    * Why doesn't CPython use a more traditional garbage collection
      scheme?

    * Why isn't all memory freed when CPython exits?

    * Why are there separate tuple and list data types?

    * How are lists implemented in CPython?

    * How are dictionaries implemented in CPython?

    * Why must dictionary keys be immutable?

    * Why doesn't list.sort() return the sorted list?

    * How do you specify and enforce an interface spec in Python?

    * Why is there no goto?

    * Why can't raw strings (r-strings) end with a backslash?

    * Why doesn't Python have a "with" statement for attribute
      assignments?

    * Why don't generators support the with statement?

    * Why are colons required for the if/while/def/class statements?

    * Why does Python allow commas at the end of lists and tuples?

  * Library and Extension FAQ

    * General Library Questions

    * Common tasks

    * Threads

    * Input and Output

    * Network/Internet Programming

    * Databases

    * Mathematics and Numerics

  * Extending/Embedding FAQ

    * Can I create my own functions in C?

    * Can I create my own functions in C++?

    * Writing C is hard; are there any alternatives?

    * How can I execute arbitrary Python statements from C?

    * How can I evaluate an arbitrary Python expression from C?

    * How do I extract C values from a Python object?

    * How do I use Py_BuildValue() to create a tuple of arbitrary
      length?

    * How do I call an object's method from C?

    * How do I catch the output from PyErr_Print() (or anything that
      prints to stdout/stderr)?

    * How do I access a module written in Python from C?

    * How do I interface to C++ objects from Python?

    * I added a module using the Setup file and the make fails; why?

    * How do I debug an extension?

    * I want to compile a Python module on my Linux system, but some
      files are missing. Why?

    * How do I tell "incomplete input" from "invalid input"?

    * How do I find undefined g++ symbols __builtin_new or
      __pure_virtual?

    * Can I create an object class with some methods implemented in C
      and others in Python (e.g. through inheritance)?

  * Python on Windows FAQ

    * How do I run a Python program under Windows?

    * How do I make Python scripts executable?

    * Why does Python sometimes take so long to start?

    * How do I make an executable from a Python script?

    * Is a "*.pyd" file the same as a DLL?

    * How can I embed Python into a Windows application?

    * How do I keep editors from inserting tabs into my Python source?

    * How do I check for a keypress without blocking?

    * How do I solve the missing api-ms-win-crt-runtime-l1-1-0.dll
      error?

  * Graphic User Interface FAQ

    * General GUI Questions

    * What GUI toolkits exist for Python?

    * Tkinter questions

  * "Why is Python Installed on my Computer?" FAQ

    * What is Python?

    * Why is Python installed on my machine?

    * Can I delete Python?

* Glossary

* About these documents

  * Contributors to the Python Documentation

* Dealing with Bugs

  * Documentation bugs

  * Using the Python issue tracker

  * Getting started contributing to Python yourself

* Copyright

* History and License

  * History of the software

  * Terms and conditions for accessing or otherwise using Python

    * PSF LICENSE AGREEMENT FOR PYTHON 3.10.12

    * BEOPEN.COM LICENSE AGREEMENT FOR PYTHON 2.0

    * CNRI LICENSE AGREEMENT FOR PYTHON 1.6.1

    * CWI LICENSE AGREEMENT FOR PYTHON 0.9.0 THROUGH 1.2

    * ZERO-CLAUSE BSD LICENSE FOR CODE IN THE PYTHON 3.10.12
      DOCUMENTATION

  * Licenses and Acknowledgements for Incorporated Software

    * Mersenne Twister

    * Sockets

    * Asynchronous socket services

    * Cookie management

    * Execution tracing

    * UUencode and UUdecode functions

    * XML Remote Procedure Calls

    * test_epoll

    * Select kqueue

    * SipHash24

    * strtod and dtoa

    * OpenSSL

    * expat

    * libffi

    * zlib

    * cfuhash

    * libmpdec

    * W3C C14N test suite

    * Audioop
