如何在string.replace中输入正则表达式？

我需要一些帮助来声明正则表达式。我的输入如下：

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

我也尝试过此方法（但似乎我使用了错误的regex语法）：

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

我不想replace从1到99 进行硬编码。。。

这个经过测试的代码段应该做到这一点：

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

编辑：这是解释其工作方式的注释版本：

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)

正则表达式是 有趣！但我强烈建议您花一两个小时来学习基础知识。对于初学者，您需要学习哪些特殊字符：需要转义的“元字符”（即，前面加反斜杠-字符类的内外规则都不同。）在以下位置有一个出色的在线教程：www .regular-expressions.info。您在那里度过的时间将使自己获得很多回报。祝您满意！

str.replace()进行固定替换。使用re.sub()代替。

我会这样（正则表达式在注释中说明）：

import re

# If you need to use the regex more than once it is suggested to compile it.
pattern = re.compile(r"</{0,}\[\d+>")

# <\/{0,}\[\d+>
# 
# Match the character “<” literally «<»
# Match the character “/” literally «\/{0,}»
#    Between zero and unlimited times, as many times as possible, giving back as needed (greedy) «{0,}»
# Match the character “[” literally «\[»
# Match a single digit 0..9 «\d+»
#    Between one and unlimited times, as many times as possible, giving back as needed (greedy) «+»
# Match the character “>” literally «>»

subject = """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>"""

result = pattern.sub("", subject)

print(result)

如果您想了解有关正则表达式的更多信息，建议阅读 Jan Goyvaerts和Steven Levithan撰写的《表达式食谱》。

最简单的方法

import re

txt='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>'

out = re.sub("(<[^>]+>)", '', txt)
print out

字符串对象的replace方法不接受正则表达式，而仅接受固定的字符串（请参见文档：http : //docs.python.org/2/library/stdtypes.html#str.replace）。

您必须使用re模块：

import re
newline= re.sub("<\/?\[[0-9]+>", "", line)

不必使用正则表达式（用于您的示例字符串）

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

>>> for w in s.split(">"):
...   if "<" in w:
...      print w.split("<")[0]
...
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

import os, sys, re, glob

pattern = re.compile(r"\<\[\d\>")
replacementStringMatchesPattern = "<[1>"

for infile in glob.glob(os.path.join(os.getcwd(), '*.txt')):
   for line in reader: 
      retline =  pattern.sub(replacementStringMatchesPattern, "", line)         
      sys.stdout.write(retline)
      print (retline)