Handy Standard Library Modules in Python
Python comes with over 200 standard library modules. In the following list, I provide to you the most commonly used ones in Python 3. Each of these modules can be imported using the import statement. Each module links to official Python documentation citing examples to work with it.
To view the helptext along with objects contained in the modules, execute help(module_name).
| S. No. | Module Name | Description |
|---|---|---|
| 1. | sys | Exposes objects and functions used by the interactive interpreter. |
| 2. | os | Enables the user to use the operating system properties to ensure cross-platform compatibility. |
| 3. | re | Provides the ever so powerful Regular Expressions, as found in Perl programming language. |
| 4. | pprint | Enables to prettify the output while printing arbitrary data structures. |
| 5. | itertools | Provides a set of functions to create various iterators. |
| 6. | functools | Provides a set of useful functions and decorators to work with other functions. |
| 7. | copy | Provides functions to copy objects properly in Python. |
| 8. | datetime | Helps manipulate date and time. |
| 9. | tkinter | Python's official GUI Toolkit. |
| 10. | calendar | Enables to print and work with calendars. |
| 11. | time | Provides time-related functions. |
| 12. | random | Helps generate random numbers and choose randomly from a sequence. |
| 13. | argparse | Helps parse command-line options, arguments and sub-commands. |
| 14. | glob | Helps find pathnames matching a given pattern, like in Unix. |
| 15. | inspect | Provides information on classes, functions and other live objects. |
| 16. | unittest | Python's library for unit testing. |
| 17. | timeit | Helps measure execution time of small code snippets. |
| 18. | webbrowser | Provides interfaces for controlling Web Browsers. |
| 19. | math | Functions for mathematical operations. |
| 20. | collections | Specialized data structures such as namedtuple, defaultdict, deque etc. |
| 21. | csv | For manipulating Comma Separated Values files. |
| 22. | sqlite3 | Interface to SQLite databases, a lightweight database for internal storage. |
| 23. | json | Enables encoding & decoding to/from JavaScript Object Notation, most commonly used data interchange format. |
| 24. | shelve | Provides a persistent dictionary-like object for serialization in Python. |
| 25. | pickle | Enables to serialize and de-serialize objects using byte streams. |
| 26. | io | Offers tools for working with input/output streams. |
| 27. | shutil | Provides high-level operations on files. |
| 28. | trace | To trace/track execution of statements/programs. |
| 29. | traceback | Helps to print stack traces of programs willingly, like in the Interactive Interpreter. |
| 30. | doctest | Executes tests written in docstrings. |
| 31. | pydoc | Generates documentation from modules. Serves as online help system by being invoked by the builtin help() function. |
| 32. | pdb | Provides an interactive source code debugger for programs. |
| 33. | logging | Implements an event-logging system for applications. |
| 34. | tempfile | Generate temporary files and directories, which are deleted automatically once the context finished. |
| 35. | array | Python's implementation of the array data type. |
| 36. | cmd | Enables the user to write command-line oriented interpreters using a simple framework. |
| 37. | heapq | Python's implementation of the heap queue algorithm, or the priority queue algorithm. |
| 38. | threading | Python module to implement multi-threading programming. |
| 39. | fnmatch | Filename matching with shell style wildcards. |
| 40. | gc | Provides access to the garbage collector. |
| 41. | decimal | Provides support for fixed point and floating point arithmetic with familiar rules and avoid the tricky representation issues associated with binary floating point. |
| 42. | statistics | Provides functions for calculating statistics of data, such as averages, standard deviation, variance etc. |
| 43. | gzip | Enables the user to compress and decompress files. |
| 44. | queue | Provides multi-producer, multi-consumer queues for use in threaded programming. |
| 45. | abc | Enables the user to define Abstract Classes in Python. |
| 46. | urlib.parse | Extract different parts of a URL. |
| 47. | urllib.request | Open URLs using Python. |
| 48. | smtplib | Send e-mails with an SMTP protocol client. |
| 49. | getpass | Have the user input password securely. |
| 50. | socket | Provides access to sockets, building blocks of network programming. |
| 51. | wsgiref | Provides functions for working with Web Server Gateway Interface environments |
| 52. | turtle | A popular graphics library in Python. |
| 53. | contextlib | Provides utilities that can be used with the with statement. |
That's it for this one. If you think we missed any useful standard library module, let us know in the comments below.
See also: 60+ Handy Third-Party Modules