Python 3 Standard Library
Introduction
Built-in Functions
Built-in Constants
Built-in Types
- Truth Value Testing
- Boolean Operations ---
and,or,not - Comparisons
- Numeric Types ---
int,float,complex - Iterator Types
- Sequence Types ---
list,tuple,range - 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
Built-in Exceptions
- Exception context
- Inheriting from built-in exceptions
- Base classes
- Concrete exceptions
- Warnings
- Exception hierarchy
Text Processing Services
string--- Common string operationsre--- Regular expression operationsdifflib--- Helpers for computing deltastextwrap--- Text wrapping and fillingunicodedata--- Unicode Databasestringprep--- Internet String Preparationreadline--- GNU readline interfacerlcompleter--- Completion function for GNU readline
Binary Data Services
Data Types
datetime--- Basic date and time typeszoneinfo--- IANA time zone supportcalendar--- General calendar-related functionscollections--- Container datatypescollections.abc--- Abstract Base Classes for Containersheapq--- Heap queue algorithmbisect--- Array bisection algorithmarray--- Efficient arrays of numeric valuesweakref--- Weak referencestypes--- Dynamic type creation and names for built-in typescopy--- Shallow and deep copy operationspprint--- Data pretty printerreprlib--- Alternaterepr()implementationenum--- Support for enumerationsgraphlib--- Functionality to operate with graph-like structures
Numeric and Mathematical Modules
numbers--- Numeric abstract base classesmath--- Mathematical functionscmath--- Mathematical functions for complex numbersdecimal--- Decimal fixed point and floating point arithmeticfractions--- Rational numbersrandom--- Generate pseudo-random numbersstatistics--- Mathematical statistics functions
Functional Programming Modules
itertools--- Functions creating iterators for efficient loopingfunctools--- Higher-order functions and operations on callable objectsoperator--- Standard operators as functions
File and Directory Access
pathlib--- Object-oriented filesystem pathsos.path--- Common pathname manipulationsfileinput--- Iterate over lines from multiple input streamsstat--- Interpretingstat()resultsfilecmp--- File and Directory Comparisonstempfile--- Generate temporary files and directoriesglob--- Unix style pathname pattern expansionfnmatch--- Unix filename pattern matchinglinecache--- Random access to text linesshutil--- High-level file operations
Data Persistence
pickle--- Python object serializationcopyreg--- Registerpicklesupport functionsshelve--- Python object persistencemarshal--- Internal Python object serializationdbm--- Interfaces to Unix "databases"sqlite3--- DB-API 2.0 interface for SQLite databases
Data Compression and Archiving
zlib--- Compression compatible with gzipgzip--- Support for gzip filesbz2--- Support for bzip2 compressionlzma--- Compression using the LZMA algorithmzipfile--- Work with ZIP archivestarfile--- Read and write tar archive files
File Formats
csv--- CSV File Reading and Writingconfigparser--- Configuration file parsernetrc--- netrc file processingplistlib--- Generate and parse Apple.plistfiles
Cryptographic Services
hashlib--- Secure hashes and message digestshmac--- Keyed-Hashing for Message Authenticationsecrets--- Generate secure random numbers for managing secrets
Generic Operating System Services
os--- Miscellaneous operating system interfacesio--- Core tools for working with streamstime--- Time access and conversionsargparse--- Parser for command-line options, arguments and sub-commandsgetopt--- C-style parser for command line optionslogging--- Logging facility for Pythonlogging.config--- Logging configurationlogging.handlers--- Logging handlersgetpass--- Portable password inputcurses--- Terminal handling for character-cell displayscurses.textpad--- Text input widget for curses programscurses.ascii--- Utilities for ASCII characterscurses.panel--- A panel stack extension for cursesplatform--- Access to underlying platform's identifying dataerrno--- Standard errno system symbolsctypes--- A foreign function library for Python
Concurrent Execution
threading--- Thread-based parallelismmultiprocessing--- Process-based parallelismmultiprocessing.shared_memory--- Shared memory for direct access across processes- The
concurrentpackage concurrent.futures--- Launching parallel taskssubprocess--- Subprocess managementsched--- Event schedulerqueue--- A synchronized queue classcontextvars--- Context Variables_thread--- Low-level threading API
Networking and Interprocess Communication
asyncio--- Asynchronous I/Osocket--- Low-level networking interfacessl--- TLS/SSL wrapper for socket objectsselect--- Waiting for I/O completionselectors--- High-level I/O multiplexingsignal--- Set handlers for asynchronous eventsmmap--- Memory-mapped file support
Internet Data Handling
email--- An email and MIME handling packagejson--- JSON encoder and decodermailbox--- Manipulate mailboxes in various formatsmimetypes--- Map filenames to MIME typesbase64--- Base16, Base32, Base64, Base85 Data Encodingsbinhex--- Encode and decode binhex4 filesbinascii--- Convert between binary and ASCIIquopri--- Encode and decode MIME quoted-printable data
Structured Markup Processing Tools
html--- HyperText Markup Language supporthtml.parser--- Simple HTML and XHTML parserhtml.entities--- Definitions of HTML general entities- XML Processing Modules
xml.etree.ElementTree--- The ElementTree XML APIxml.dom--- The Document Object Model APIxml.dom.minidom--- Minimal DOM implementationxml.dom.pulldom--- Support for building partial DOM treesxml.sax--- Support for SAX2 parsersxml.sax.handler--- Base classes for SAX handlersxml.sax.saxutils--- SAX Utilitiesxml.sax.xmlreader--- Interface for XML parsersxml.parsers.expat--- Fast XML parsing using Expat
Internet Protocols and Support
webbrowser--- Convenient web-browser controllerwsgiref--- WSGI Utilities and Reference Implementationurllib--- URL handling modulesurllib.request--- Extensible library for opening URLsurllib.response--- Response classes used by urlliburllib.parse--- Parse URLs into componentsurllib.error--- Exception classes raised by urllib.requesturllib.robotparser--- Parser for robots.txthttp--- HTTP moduleshttp.client--- HTTP protocol clientftplib--- FTP protocol clientpoplib--- POP3 protocol clientimaplib--- IMAP4 protocol clientsmtplib--- SMTP protocol clientuuid--- UUID objects according to RFC 4122socketserver--- A framework for network servershttp.server--- HTTP servershttp.cookies--- HTTP state managementhttp.cookiejar--- Cookie handling for HTTP clientsxmlrpc--- XMLRPC server and client modulesxmlrpc.client--- XML-RPC client accessxmlrpc.server--- Basic XML-RPC serversipaddress--- IPv4/IPv6 manipulation library
Multimedia Services
Internationalization
Program Frameworks
turtle--- Turtle graphicscmd--- Support for line-oriented command interpretersshlex--- Simple lexical analysis
Graphical User Interfaces with Tk
tkinter--- Python interface to Tcl/Tktkinter.colorchooser--- Color choosing dialogtkinter.font--- Tkinter font wrapper- Tkinter Dialogs
tkinter.messagebox--- Tkinter message promptstkinter.scrolledtext--- Scrolled Text Widgettkinter.dnd--- Drag and drop supporttkinter.ttk--- Tk themed widgetstkinter.tix--- Extension widgets for Tk- IDLE
Development Tools
typing--- Support for type hintspydoc--- 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 examplesunittest--- Unit testing frameworkunittest.mock--- mock object libraryunittest.mock--- getting started- 2to3 --- Automated Python 2 to 3 code translation
test--- Regression tests package for Pythontest.support--- Utilities for the Python test suitetest.support.socket_helper--- Utilities for socket teststest.support.script_helper--- Utilities for the Python execution teststest.support.bytecode_helper--- Support tools for testing correct bytecode generationtest.support.threading_helper--- Utilities for threading teststest.support.os_helper--- Utilities for os teststest.support.import_helper--- Utilities for import teststest.support.warnings_helper--- Utilities for warnings tests
Debugging and Profiling
- Audit events table
bdb--- Debugger frameworkfaulthandler--- Dump the Python tracebackpdb--- The Python Debugger- The Python Profilers
timeit--- Measure execution time of small code snippetstrace--- Trace or track Python statement executiontracemalloc--- Trace memory allocations
Software Packaging and Distribution
distutils--- Building and installing Python modulesensurepip--- Bootstrapping thepipinstallervenv--- Creation of virtual environmentszipapp--- Manage executable Python zip archives
Python Runtime Services
sys--- System-specific parameters and functionssysconfig--- Provide access to Python's configuration informationbuiltins--- Built-in objects__main__--- Top-level code environmentwarnings--- Warning controldataclasses--- Data Classescontextlib--- Utilities forwith-statement contextsabc--- Abstract Base Classesatexit--- Exit handlerstraceback--- Print or retrieve a stack traceback__future__--- Future statement definitionsgc--- Garbage Collector interfaceinspect--- Inspect live objectssite--- Site-specific configuration hook
Custom Python Interpreters
Importing Modules
zipimport--- Import modules from Zip archivespkgutil--- Package extension utilitymodulefinder--- Find modules used by a scriptrunpy--- Locating and executing Python modulesimportlib--- The implementation ofimport- Using
importlib.metadata
Python Language Services
ast--- Abstract Syntax Treessymtable--- Access to the compiler's symbol tablestoken--- Constants used with Python parse treeskeyword--- Testing for Python keywordstokenize--- Tokenizer for Python sourcetabnanny--- Detection of ambiguous indentationpyclbr--- Python module browser supportpy_compile--- Compile Python source filescompileall--- Byte-compile Python librariesdis--- Disassembler for Python bytecodepickletools--- Tools for pickle developers
MS Windows Specific Services
msvcrt--- Useful routines from the MS VC++ runtimewinreg--- Windows registry accesswinsound--- Sound-playing interface for Windows
Unix Specific Services
posix--- The most common POSIX system callspwd--- The password databasegrp--- The group databasetermios--- POSIX style tty controltty--- Terminal control functionspty--- Pseudo-terminal utilitiesfcntl--- Thefcntlandioctlsystem callsresource--- Resource usage informationsyslog--- Unix syslog library routines
Superseded Modules
aifc--- Read and write AIFF and AIFC filesasynchat--- Asynchronous socket command/response handlerasyncore--- Asynchronous socket handleraudioop--- Manipulate raw audio datacgi--- Common Gateway Interface supportcgitb--- Traceback manager for CGI scriptschunk--- Read IFF chunked datacrypt--- Function to check Unix passwordsimghdr--- Determine the type of an imageimp--- Access the import internalsmailcap--- Mailcap file handlingmsilib--- Read and write Microsoft Installer filesnis--- Interface to Sun's NIS (Yellow Pages)nntplib--- NNTP protocol clientoptparse--- Parser for command line optionsossaudiodev--- Access to OSS-compatible audio devicespipes--- Interface to shell pipelinessmtpd--- SMTP Serversndhdr--- Determine type of sound filespwd--- The shadow password databasesunau--- Read and write Sun AU filestelnetlib--- Telnet clientuu--- Encode and decode uuencode filesxdrlib--- Encode and decode XDR data