python regex匹配文件名但不显示

Question

I have a few files in the folder and I want to find out the content and match its file name. But when I use re.search to achieve my goal I can only get 'None'. Anyone could help?

import re
xe = r'D:\ABC\cc123.xml'
re.search('cc*?.xml', xe)

Answer 1

(Though there is an accepted answer, I don't feel the answer is clear for other people, and there is still room to improve, so I added a new answer here)

The problem is simply OP is using a wrong regex: cc*?.xml

* means any occurrence of the preceding token (which means c in your case) *? is a reluctant match any occurrence. . means any character

Which means what you are trying to do is match a string which is:

• a c
• followed by any occurrence of c
• followed by any character
• followed by xml

Example of matching strings are c.xml ccccccAxml etc.

What you were trying to do, I believe is

cc.*?\.xml

which means matching

• cc
• .*? : followed by any occurrence of any character, matching as few as possible
• \\. : followed by a dot (note the difference of \\. vs . )
• followed by xml

Answer 2

How about something like this with a small tweak?

import re
xe = 'D:\ABC\cc123.xml'
print (re.search('cc.*?.xml', xe).group())

output:

cc123.xml