How to Strip Unwanted Text with Python Regex: A Step‑by‑Step Guide

Introduction

In a recent Python community discussion a user asked about using Python regular expressions to remove certain patterns from a text file. The author proposes a solution using the re module.

Implementation

The provided script opens a text file (e.g., "Journey to the West.txt") with GBK encoding, reads its content, and applies re.sub(r'#.*?#', '', data) to delete text between hash symbols. The result is written back to the same file.

import re
filename = '西游记全集（吴承恩）.txt'
with open(filename, 'r', encoding='gbk') as f:
    data = f.read()

result = re.sub(r'#.*?#', '', data)

with open(filename, 'w', encoding='gbk') as f2:
    f2.write(result)

To also remove multiline comments, the re.S flag can be added so that the newline character is treated as a normal character within the pattern.

Conclusion

The article demonstrates how to use Python regular expressions for batch text cleaning, provides a complete code example, and explains the effect of the re.S flag for matching across lines.