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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Python by Example

  1. Python Basics
  2. Print Version String
  3. Builtin Help
  4. Quote String
  5. String Operations
  6. String Methods
  7. Format String
  8. True, False
  9. if then else
  10. for, while, Loops
  11. List Basics
  12. Loop Thru List
  13. Map Function to List
  14. List Comprehension
  15. List Methods
  16. Dictionary
  17. Loop Thru Dict
  18. Dict Methods
  19. Function
  20. Class
  21. List Modules
  22. Write a Module
  23. Unicode 🐍


  1. Regex Basics
  2. Regex Reference

Text Processing

  1. Read/Write File
  2. Traverse Directory
  3. Manipulate 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
  5. Check Page Load Size
  6. Thumbnail Generation


  1. JSON
  2. Find Script Path
  3. Get Env Var
  4. System Call
  5. Decompress Gzip
  6. Complex Numbers


  1. Sort
  2. Copy Nested List
  3. Tuple vs List
  4. Sets, Union, Intersection
  5. Closure in Python 2
  6. Decorator
  7. Append String in Loop
  8. Timing f timeit
  9. Keyword Arg Default Value Unstable