Python string.replace正则表达式[复制]

本文翻译自：Python string.replace regular expression [duplicate]

This question already has an answer here: 这个问题在这里已有答案：

• How to input a regex in string.replace? 如何在string.replace中输入正则表达式？ 7 answers 7个答案

I have a parameter file of the form: 我有一个表格的参数文件：

parameter-name parameter-value

Where the parameters may be in any order but there is only one parameter per line. 参数可以按任何顺序排列，但每行只有一个参数。 I want to replace one parameter's parameter-value with a new value. 我想用一个新值替换一个参数的parameter-value值。

I am using a line replace function posted previously to replace the line which uses Python's string.replace(pattern, sub) . 我使用之前发布的行替换函数来替换使用Python的string.replace(pattern, sub) 。 The regular expression that I'm using works for instance in vim but doesn't appear to work in string.replace() . 我正在使用的正则表达式在vim中工作，但似乎不能在string.replace() 。

Here is the regular expression that I'm using: 这是我正在使用的正则表达式：

line.replace("^.*interfaceOpDataFile.*$/i", "interfaceOpDataFile %s" % (fileIn))

Where "interfaceOpDataFile" is the parameter name that I'm replacing (/i for case-insensitive) and the new parameter value is the contents of the fileIn variable. 其中"interfaceOpDataFile"是我要替换的参数名称（/ i表示不区分大小写），新参数值是fileIn变量的内容。

Is there a way to get Python to recognize this regular expression or else is there another way to accomplish this task? 有没有办法让Python识别这个正则表达式，否则还有另一种方法可以完成这个任务吗？

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#1楼

参考：https://stackoom.com/question/189m9/Python-string-replace正则表达式-复制

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#2楼

str.replace() ^{v2 |} str.replace() ^{v2 | v3} does not recognize regular expressions. ^v3无法识别正则表达式。

To perform a substitution using a regular expression, use re.sub() ^{v2 |} 要使用正则表达式执行替换，请使用re.sub() ^{v2 | v3} . ^v3 。

For example: 例如：

import re

line = re.sub(
           r"(?i)^.*interfaceOpDataFile.*$", 
           "interfaceOpDataFile %s" % fileIn, 
           line
       )

In a loop, it would be better to compile the regular expression first: 在循环中，最好先编译正则表达式：

import re

regex = re.compile(r"^.*interfaceOpDataFile.*$", re.IGNORECASE)
for line in some_file:
    line = regex.sub("interfaceOpDataFile %s" % fileIn, line)
    # do something with the updated line

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#3楼

You are looking for the re.sub function. 您正在寻找re.sub功能。

import re
s = "Example String"
replaced = re.sub('[ES]', 'a', s)
print replaced 

will print axample atring 将打印axample atring

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#4楼

re.sub is definitely what you are looking for. re.sub绝对是你要找的。 And so you know, you don't need the anchors and the wildcards. 所以你知道，你不需要锚和通配符。

re.sub(r"(?i)interfaceOpDataFile", "interfaceOpDataFile %s" % filein, line)

will do the same thing--matching the first substring that looks like "interfaceOpDataFile" and replacing it. 将做同样的事情 - 匹配看起来像“interfaceOpDataFile”的第一个子串并替换它。

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#5楼

As a summary 作为总结

import sys
import re

f = sys.argv[1]
find = sys.argv[2]
replace = sys.argv[3]
with open (f, "r") as myfile:
     s=myfile.read()
ret = re.sub(find,replace, s)   # <<< This is where the magic happens
print ret