如何在字符串中搜索文本并替换为其值

Question

I need to search for image_bid in string s and if exists need to replace that string with its value DEBUG in this case,I tried the following but doesn't seem to work,can anyone suggest how can I do that?

import re
s = "cols/sel/Pkg/Bin/LA/${image_bid:DEBUG}/"

match = re.search('image_bid:(\w+)',s)
print match.group(1)

if match:
    final_value = s.replace('image_bid:(\w+)',match.group(1))
print final_value

MY OUTPUT:-
cols/sel/Pkg/Bin/LA/${image_bid:DEBUG}/

Expected output:-
cols/sel/Pkg/Bin/LA/DEBUG

Answer 1

The method replace() returns a copy of the string in which the occurrences of old have been replaced with new, optionally restricting the number of replacements to max.

It doesn't seem like the replace method for string support regular expression, use re.sub instead:

if match:
    final_value = re.sub(r'\${image_bid:\w+}',match.group(1), s)
print final_value
# cols/sel/Pkg/Bin/LA/DEBUG/

Answer 2

你可能想要这样的东西

final_value = re.sub(r'\$\{image_bid\:(\w+)\}/', r'\1', s)