Regex to replace between second occurance of symbol A and symbol B

Question

I have an example string to match:

s = 'https://john:ABCDE@api.example.com'

I am trying to replace the string ABCDE between the 2nd colon and the first occurrance of @. So my desired output is:

s_out = 'https://john:REPLACED@api.example.com'

My current code is:

import re
s_out = re.sub(r":*(.+)@api.example.com", 'REPLACED', s)

But i am unable to replace this currently.

Answer 1

You can start the match with the colon, and then prevent matching either : or @ using a negated character class

Capture in a group starting from the @ sign, which you can then use in the replacement.

:[^\s:@]*(@api\.example\.com)

And replace with

:REPLACED\1

See a regex101 demo.

Example

import re

s = 'https://john:ABCDE@api.example.com'
pattern = r":[^\s:@]*(@api\.example\.com)"
s_out = re.sub(pattern, r":REPLACED\1", s)
print(s_out)

Output

https://john:REPLACED@api.example.com