Python Regex Reference

By Xah Lee. Date: . Last updated: .

Regex Basics Tutorial

Python: Regex Basics

Regex Functions

Python Regex Functions

For vast majority of uses, you want the .search(…) and .sub(…) and .split(…) functions.

Regex Objects

Python Regex Object and Methods

For writing code using Object Oriented style.

Python Regex Flags

Python Regex Flags

Options for regex methods that change regex pattern's meaning.

Regex Match Objects

Python Regex Match Object

Some function or method return their result as object called “MatchObject”.

Regex Pattern Syntax

Python Regex Syntax

Notes and References

Note: This document was originally a rewrite of Python 2.4's Official Documentation of its RE module (, strictly following its style and format. It was written in 2005. However, it has since been rewritten as independent tutorial and reference. For detail, see: Notes on Rewriting Python Regex Documentation

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  1. Python 3 Basics
  2. Python 2 Basics
  3. Python 2 and 3 Difference
  4. Print Version
  5. Builtin Help
  6. Quote String
  7. String Methods
  8. Format String
  9. Operators
  10. Complex Numbers
  11. True, False
  12. if then else
  13. Loop
  14. List Basics
  15. Loop Thru List
  16. Map f to List
  17. Copy Nested List
  18. List Comprehension
  19. List Methods
  20. Sort
  21. Dictionary
  22. Loop Thru Dict
  23. Dict Methods
  24. Tuple
  25. Sets
  26. Function
  27. Closure
  28. 2 Closure
  29. Decorator
  30. Class
  31. Object, ID, Type
  32. List Modules
  33. Write a Module
  34. Unicode 🐍


  1. Regex Basics
  2. Regex Reference

Text Processing

  1. Read/Write File
  2. Traverse Directory
  3. File Path
  4. Process Unicode
  5. Convert File Encoding
  6. Find Replace in dir
  7. Find Replace by Regex
  8. Count Word Frequency


  1. Send Email
  2. GET Web Page
  3. Web Crawler


  1. JSON
  2. Find Script Path
  3. Get Env Var
  4. System Call
  5. Decompress Gzip
  6. Append String in Loop
  7. Timing f timeit
  8. Keyword Arg Default Value Unstable
  9. Check Page Load Size
  10. Thumbnail Generation