Python standard library

See also Supported platforms and architectures, History of Python, and Python Import.

sys.stdlib_module_names

• Python 3.13: 278 modules

  • Remove (22): _crypt, _msi, aifc, audioop, cgi, cgitb, chunk, crypt, imghdr, lib2to3, mailcap, msilib, nis, nntplib, ossaudiodev, pipes, sndhdr, spwd, sunau, telnetlib, uu, xdrlib

• Python 3.12: 300 modules

  • Add (3): _sha2, _pylong, _pydatetime

  • Remove (8): _bootsubprocess, _sha256, _sha512, asynchat, asyncore, distutils, imp, smtpd

• Python 3.11: 305 modules

  • Add (3): tomllib, _tokenize and _typing

  • Remove (1): binhex

• Python 3.10: 303 modules

sys.stdlib_module_names was added to Python 3.10. For Python 2.6 to 3.9, the 3rd party stdlib-list module can be used.

Talks

• 2023: Language Summit 2023: What is the stdlib for? by Brett Cannon

• 2021: The 2021 Python Language Summit: What Is the stdlib? by Brett Cannon

• 2019: Batteries Included, But They’re Leaking by Amber Brown

Maintain the stdlib outside Python?

• 2021: cpython_hack: David Beazley’s experiment to make the Python stdlib as small as possible. The stdlib is made of 7 Python modules and 3 C extensions.

  stdlib Python modules:

  • genericpath

  • io

  • os

  • posixpath

  • site

  • stat

  • types

  stdlib C extensions:

  • _stat

  • posix

  • readline

  There is an extra Lib/__phello__.foo.py module, but it’s only used for tests.

• 2019: If Python started moving more code out of the stdlib and into PyPI packages, what technical mechanisms could packaging use to ease that transition? by Nathaniel J. Smith

• PEP 360 – Externally Maintained Packages

Stdlib history

Python 3.13

Python 3.13 removed 20 module:

• lib2to3: deprecated in Python 3.11, issue #104780, PEP 617

• aifc: PEP 594

• audioop: PEP 594

• cgi: PEP 594

• cgitb: PEP 594

• chunk: PEP 594

• crypt: PEP 594

• imghdr: PEP 594

• mailcap: PEP 594

• msilib: PEP 594

• nis: PEP 594

• nntplib: PEP 594

• ossaudiodev: PEP 594

• pipes: PEP 594

• sndhdr: PEP 594

• spwd: PEP 594

• sunau: PEP 594

• telnetlib: PEP 594

• uu: PEP 594

• xdrlib: PEP 594

Python 3.12

Python 3.12 removed 5 module:

• asynchat: deprecated in Python 3.6, PEP 594

• asyncore: deprecated in Python 3.6, PEP 594

• distutils: deprecated in Python 3.10, PEP 632 - Deprecate distutils module

• imp: deprecated in Python 3.5, issue #98040, PR #98573, replaced with importlib

• smtpd: deprecated in Python 3.6, PEP 594

PEP 594

PEP 594 – Removing dead batteries from the standard library scheduled the removal of many stdlib modules in Python 3.12 and 3.13.

Python 3.11

Python 3.11 added 1 module:

• tomllib: PEP 680 – tomllib: Support for Parsing TOML in the Standard Library

Python 3.11 added 1 sub-module to existing packages:

• wsgiref.types

Python 3.11 removed 1 module:

• binhex: deprecated in Python 3.9, issue #89248.

Note: asyncore, asynchat, smtplib were removed in Python 3.11, but then the SC asked to add them back

Python 3.10

Python 3.10 removed 3 modules:

• formatter: deprecated in Python 3.4, issue #86465, python-dev thread

• parser: deprecated in Python 3.9, PEP 617 (PEG parser)

• symbol: deprecated in Python 3.9, PEP 617

Python 3.9

Python 3.9 added 2 modules:

• graphlib

• zoneinfo

Python 3.9 removed 2 modules:

• dummy_threading: deprecated in Python 3.7; Python 3.7 requires threads to build: bpo-31370.

• _dummy_thread: same.

Python 3.8

Python 3.8 added 1 sub-module to existing packages:

• importlib.metadata

Python 3.8 removed 1 module:

• macpath: deprecated in Python 3.7, issue #79652, Mac OS 9 is no longer used.

Python 3.7

Python 3.7 added 2 modules:

• contextvars: PEP 567 – Context Variables

• dataclasses: PEP 557 – Data Classes

Python 3.7 added 1 sub-module to existing packages:

• importlib.resources: issue #76429

Python 3.7 removed 2 modules:

• fpectl: issue #73323, it was never enabled by default, never worked correctly on x86-64, and it changed the Python ABI in ways that caused unexpected breakage of C extensions.

• macurl2path: issue #72512

Python 3.6

Python 3.6 added 1 module:

• secrets: PEP 506 – Adding A Secrets Module To The Standard Library

Python 3.6 removed 6 modules:

• CDIO: issue #72214

• CDROM: issue #72214

• DLFCN: issue #72214

• IN: issue #72214

• STROPTS: issue #72214

• TYPES: issue #72214

issue #72214: These removed modules were undocumented. They had been available in the platform specific Lib/plat-*/ directories, but were chronically out of date, inconsistently available across platforms, and unmaintained.

Python 3.5

Python 3.5 added 2 modules:

• typing PEP 484 – Type Hints and PEP 483 – The Theory of Type Hints

• zipapp: PEP 441 – Improving Python ZIP Application Support

Python 3.4

Python 3.4 added 7 modules:

• asyncio: PEP 3156 – Asynchronous IO Support Rebooted: the “asyncio” Module

• ensurepip

• enum: PEP 435 – Adding an Enum type to the Python standard library

• pathlib: PEP 428 – The pathlib module – object-oriented filesystem paths

• selectors: PEP 3156

• statistics: PEP 450 – Adding A Statistics Module To The Standard Library

• tracemalloc: PEP 454 – Add a new tracemalloc module to trace Python memory allocations

Python 3.3

Python 3.3 added 4 modules:

• faulthandler: issue #55602

• ipaddress: PEP 3144 – IP Address Manipulation Library for the Python Standard Library

• lzma: issue #50964

• venv: PEP 405 – Python Virtual Environments

Python 3.3 added 1 sub-module to existing packages:

• unittest.mock

Python 3.2

Python 3.2 added 2 modules:

• argparse: PEP 389 – argparse - New Command Line Parsing Module

• concurrent.futures: PEP 3148 – futures - execute computations asynchronously

Python 3.1

Python 3.1 added 1 module:

• importlib

Python 3.1 added 1 sub-module to existing packages:

• tkinter.ttk

Python 3.0

Python 3.0 removed 74 stdlib modules, related to PEP 3108.

Moreover, many Python 2.7 modules have been renamed by PEP 3108.

Removed Mac modules (24):

• aepack

• aetools

• aetypes

• buildtools

• Carbon

• cfmfile

• ColorPicker

• EasyDialogs

• findertools

• fm

• FrameWork

• gensuitemodule

• ic

• icopen

• mac

• macerrors

• MacOS

• macosa

• macostools

• macresource

• MiniAEFrame

• Nav

• PixMapWrapper

• videoreader

Removed IRIX modules (7):

• al

• DEVICE

• flp

• gl: Functions from the Silicon Graphics Graphics Library.

• imgfile: Support for SGI imglib files

• jpeg: Read and write JPEG files

• sgi: random SGI-specific things

Removed modules, replaced by the email package (5):

• mimetools

• MimeWriter

• mimify

• multifile

• rfc822

Other removed modules (38):

• audiodev: Classes for manipulating audio devices (currently only for Sun and SGI)

• Bastion: Providing restricted access to objects

• bsddb

• Canvas (tk)

• cd: CD Audio Library

• commands: Utility functions for running external commands

• compiler: analyze Python source code and generating Python bytecode

• dircache: read directory listing with cache

• dl: dl.open()

• exceptions: Standard exception classes

• FixTk: Delay import _tkinter until we have set TCL_LIBRARY, imported by Tkinter`

• fl: interface to Mark Overmars’ FORMS Library

• fpformat: General floating point formatting functions

• future_builtins: Python 3 builtins

• ihooks: Import hook support

• imageop: Manipulate raw image data, replaced with PIL/Pillow

• imputil: Import utilities

• linuxaudiodev: Linux audio device (/dev/dsp) for python, replaced by ossaudiodev.

• markupbase: Renamed to _markupbase, used by html.parser

• md5: Replaced by hashlib

• mhlib: Manipulate MH mailboxes from Python

• mutex: Lock and queue for mutual exclusion

• new: Interface to the creation of runtime implementation objects

• os2emxpath: Common operations on OS/2 pathnames

• popen2: Subprocesses with accessible I/O streams

• posixfile: File-like objects with locking support

• rexec: Restricted execution framework

• sets: Unordered collections of unique elements, replaced by set() built-in type

• sgmllib: Simple SGML parser

• sha: Replaced by hashlib

• sre: Replaced by re

• statvfs: Replaced by os.statvfs()

• stringold: Collection of string operations

• strop: Common string manipulations, optimized for speed (C extension)

• sunaudiodev (SunOS): Access to Sun audio hardware

• toaiff: Convert “arbitrary” sound files to AIFF (Apple and SGI’s audio format)

• user: Hook to allow user-specified customization code to run

• xmllib: Parser for XML, using the derived class as static DTD.