The Python Standard Library

While The Python Language Reference describes the exact syntax and semantics of the Python language, this library reference manual describes the standard library that is distributed with Python. It also describes some of the optional components that are commonly included in Python distributions.

Python’s standard library is very extensive, offering a wide range of facilities as indicated by the long table of contents listed below. The library contains built-in modules (written in C) that provide access to system functionality such as file I/O that would otherwise be inaccessible to Python programmers, as well as modules written in Python that provide standardized solutions for many problems that occur in everyday programming. Some of these modules are explicitly designed to encourage and enhance the portability of Python programs by abstracting away platform-specifics into platform-neutral APIs.

The Python installers for the Windows platform usually include the entire standard library and often also include many additional components. For Unix-like operating systems Python is normally provided as a collection of packages, so it may be necessary to use the packaging tools provided with the operating system to obtain some or all of the optional components.

In addition to the standard library, there is an active collection of hundreds of thousands of components (from individual programs and modules to packages and entire application development frameworks), available from the Python Package Index.

• 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
  • Boolean Type - bool
  • Iterator Types
  • Sequence Types — list, tuple, range
  • Text and Binary Sequence Type Methods Summary
  • Text Sequence Type — str
  • Binary Sequence Types — bytes, bytearray, memoryview
  • Set Types — set, frozenset
  • Mapping Types — dict
  • Context Manager Types
  • Type Annotation Types — Generic Alias, Union
  • Other Built-in Types
  • Special Attributes
  • Integer string conversion length limitation
• Built-in Exceptions
  • Exception context
  • Inheriting from built-in exceptions
  • Base classes
  • Concrete exceptions
  • Warnings
  • Exception groups
  • Exception hierarchy
• Text Processing Services
  • string — Common string operations
  • string.templatelib — Support for template string literals
  • re — Regular expression operations
  • difflib — Helpers for computing deltas
  • textwrap — Text wrapping and filling
  • unicodedata — Unicode Database
  • stringprep — Internet String Preparation
  • readline — GNU readline interface
  • rlcompleter — Completion function for GNU readline
• Binary Data Services
  • struct — Interpret bytes as packed binary data
  • codecs — Codec registry and base classes
• Data Types
  • datetime — Basic date and time types
  • zoneinfo — IANA time zone support
  • calendar — General calendar-related functions
  • collections — Container datatypes
  • collections.abc — Abstract Base Classes for Containers
  • heapq — Heap queue algorithm
  • bisect — Array bisection algorithm
  • array — Efficient arrays of numeric values
  • weakref — Weak references
  • types — Dynamic type creation and names for built-in types
  • copy — Shallow and deep copy operations
  • pprint — Data pretty printer
  • reprlib — Alternate repr() implementation
  • enum — Support for enumerations
  • graphlib — Functionality to operate with graph-like structures
• Numeric and Mathematical Modules
  • numbers — Numeric abstract base classes
  • math — Mathematical functions
  • cmath — Mathematical functions for complex numbers
  • decimal — Decimal fixed-point and floating-point arithmetic
  • fractions — Rational numbers
  • random — Generate pseudo-random numbers
  • statistics — Mathematical statistics functions
• Functional Programming Modules
  • itertools — Functions creating iterators for efficient looping
  • functools — Higher-order functions and operations on callable objects
  • operator — Standard operators as functions
• File and Directory Access
  • pathlib — Object-oriented filesystem paths
  • os.path — Common pathname manipulations
  • stat — Interpreting stat() results
  • filecmp — File and Directory Comparisons
  • tempfile — Generate temporary files and directories
  • glob — Unix style pathname pattern expansion
  • fnmatch — Unix filename pattern matching
  • linecache — Random access to text lines
  • shutil — High-level file operations
• Data Persistence
  • pickle — Python object serialization
  • copyreg — Register pickle support functions
  • shelve — Python object persistence
  • marshal — Internal Python object serialization
  • dbm — Interfaces to Unix “databases”
  • sqlite3 — DB-API 2.0 interface for SQLite databases
• Data Compression and Archiving
  • The compression package
  • compression.zstd — Compression compatible with the Zstandard format
  • zlib — Compression compatible with gzip
  • gzip — Support for gzip files
  • bz2 — Support for bzip2 compression
  • lzma — Compression using the LZMA algorithm
  • zipfile — Work with ZIP archives
  • tarfile — Read and write tar archive files
• File Formats
  • csv — CSV File Reading and Writing
  • configparser — Configuration file parser
  • tomllib — Parse TOML files
  • netrc — netrc file processing
  • plistlib — Generate and parse Apple .plist files
• Cryptographic Services
  • hashlib — Secure hashes and message digests
  • hmac — Keyed-Hashing for Message Authentication
  • secrets — Generate secure random numbers for managing secrets
• Generic Operating System Services
  • os — Miscellaneous operating system interfaces
  • io — Core tools for working with streams
  • time — Time access and conversions
  • logging — Logging facility for Python
  • logging.config — Logging configuration
  • logging.handlers — Logging handlers
  • platform — Access to underlying platform’s identifying data
  • errno — Standard errno system symbols
  • ctypes — A foreign function library for Python
• Command-line interface libraries
  • argparse — Parser for command-line options, arguments and subcommands
  • optparse — Parser for command line options
  • getpass — Portable password input
  • fileinput — Iterate over lines from multiple input streams
  • curses — Terminal handling for character-cell displays
  • curses.textpad — Text input widget for curses programs
  • curses.ascii — Utilities for ASCII characters
  • curses.panel — A panel stack extension for curses
  • cmd — Support for line-oriented command interpreters
• Concurrent Execution
  • threading — Thread-based parallelism
  • multiprocessing — Process-based parallelism
  • multiprocessing.shared_memory — Shared memory for direct access across processes
  • The concurrent package
  • concurrent.futures — Launching parallel tasks
  • concurrent.interpreters — Multiple interpreters in the same process
  • subprocess — Subprocess management
  • sched — Event scheduler
  • queue — A synchronized queue class
  • contextvars — Context Variables
  • _thread — Low-level threading API
• Networking and Interprocess Communication
  • asyncio — Asynchronous I/O
  • socket — Low-level networking interface
  • ssl — TLS/SSL wrapper for socket objects
  • select — Waiting for I/O completion
  • selectors — High-level I/O multiplexing