如何在python中使用RE组替换字符串？

Question

I have a problem when using RE module in python:

import re
url='http://list.xxx.com/0-20356-1-0-0-0-0-0-0-0-269036.html'
re_rule=re.compile('.+20356\-(\d{1,3})-0-0-0.+')
new_url=re_rule.sub('2 \1')

As I wish, the new_url would be ' http://list.xxx.com/0-20356-2-0-0-0-0-0-0-0-269036.html ', but python returns new_url=2 .
I know I had make mistakes when using re module. Which mistakes had I make and how to correct them?

Answer 1

Given your example, why even bother using re ?

url = 'http://list.xxx.com/0-20356-1-0-0-0-0-0-0-0-269036.html'
new_url = url.replace('-1-', '-2-')
print(new_url)

produces what you're looking for:

http://list.xxx.com/0-20356-2-0-0-0-0-0-0-0-269036.html