如何在 string.replace 中输入正则表达式? [英] How to input a regex in string.replace?

问题描述

我需要一些关于声明正则表达式的帮助.我的输入如下:

I need some help on declaring a regex. My inputs are like the following:

this is a paragraph with<[1> in between</[1> and then there are cases ... where the<[99> number ranges from 1-100</[99>. 
and there are many other lines in the txt files
with<[3> such tags </[3>

所需的输出是:

this is a paragraph with in between and then there are cases ... where the number ranges from 1-100. 
and there are many other lines in the txt files
with such tags

我已经试过了:

#!/usr/bin/python
import os, sys, re, glob
for infile in glob.glob(os.path.join(os.getcwd(), '*.txt')):
    for line in reader: 
        line2 = line.replace('<[1> ', '')
        line = line2.replace('</[1> ', '')
        line2 = line.replace('<[1>', '')
        line = line2.replace('</[1>', '')

        print line

我也试过这个(但似乎我使用了错误的正则表达式语法):

I've also tried this (but it seems like I'm using the wrong regex syntax):

    line2 = line.replace('<[*> ', '')
    line = line2.replace('</[*> ', '')
    line2 = line.replace('<[*>', '')
    line = line2.replace('</[*>', '')

我不想将 replace 从 1 硬编码到 99 ...

I dont want to hard-code the replace from 1 to 99 . . .

推荐答案

这个经过测试的代码片段应该可以:

This tested snippet should do it:

import re
line = re.sub(r"</?\[\d+>", "", line)

这是解释其工作原理的注释版本:

Here's a commented version explaining how it works:

line = re.sub(r"""
  (?x) # Use free-spacing mode.
  <    # Match a literal '<'
  /?   # Optionally match a '/'
  \[   # Match a literal '['
  \d+  # Match one or more digits
  >    # Match a literal '>'
  """, "", line)

正则表达式有趣！但我强烈建议花一两个小时学习基础知识.对于初学者，您需要了解哪些字符是特殊的:"metacharacters" 哪些需要转义(即在前面放置一个反斜杠 - 并且字符类内外的规则不同.)有优秀的在线教程:www.regular-expressions.info.你在那里度过的时间会物有所值.快乐的正则表达式！

Regexes are fun! But I would strongly recommend spending an hour or two studying the basics. For starters, you need to learn which characters are special: "metacharacters" which need to be escaped (i.e. with a backslash placed in front - and the rules are different inside and outside character classes.) There is an excellent online tutorial at: www.regular-expressions.info. The time you spend there will pay for itself many times over. Happy regexing!

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