How to remove patterned texts surrounding a nested text on a string using regex?

Question

I have a text txt = 'The fat \m{cat sat} on \m{the} mat.' which I hope to output 'The fat cat sat on the mat.'

I have tried the following two ways:

re.sub(r'\\m\{(.*)\}', '', txt) 
# output: 'The fat  mat.'

re.sub(r'\\m\{(?=.*)\}', '', txt) 
# output: 'The fat \\m{cat sat} on \\m{the} mat.'

Why is that and how should I do?

Answer 1

You can modify your own regex a bit to make it work

• Use backreference to replace value instead of just empty string
• Also make you regex lazy i.e (.*) -> (.*?) or ([^}]*)

---

import re
txt = 'The fat \m{cat sat} on \m{the} mat.';
r = re.sub(r'\\m\{(.*?)\}', "\g<1>", txt);
print(r);      

//The fat cat sat on the mat.

Note:- you can use r"\1" or "\\1" instead of \g<1> to back reference the captured group