python regex replace redundant words with special characters

Asked Mar 19 '20 at 16:28

Active Mar 19 '20 at 16:28

Viewed 35 times

I am trying to put together a regex expression that removes all occurring redundant words.

re.sub(r'\b([a-zA-Z0-9_]{1,})(\s{1,}\1\b)+', '\\1', "removing redundant redundant redundant")
>>> 'removing redundant'

Now I am stuck at the level where the redundant words start with special characters

re.sub(r'\b([#a-zA-Z0-9_]{1,})(\s{1,}\1\b)+', '\\1', "removing red#undant red#undant red#undant")
>>> 'removing red#undant'

re.sub(r'\b([#a-zA-Z0-9_]{1,})(\s{1,}\1\b)+', '\\1', "removing #redundant #redundant #redundant")
>>> 'removing #redundant #redundant #redundant'

I tried putting backslashes and many other combinations but nothing worked. I am sure there is something fundamental that i am not understanding or missing ...

thanks

asked Mar 19 '20 at 16:28

Cobry

4,348
8
33
49

That is because of `\b` whose meaning is context dependent. Replace with the unambiguous word boundaries, or precise their meaning with lookaheads. – Wiktor Stribiżew Mar 19 '20 at 16:32
what do you mean by unambiguous word boundaries ? – Cobry Mar 19 '20 at 16:42
Read my answer. – Wiktor Stribiżew Mar 19 '20 at 16:52
Man if i understood i wouldn't be asking again :) regex is not my forté ... – Cobry Mar 19 '20 at 16:57
See https://ideone.com/lo9uQT, `\b...\b` must be replaced with `(?<!\w)...(?!\w)`. As explained [here](https://stackoverflow.com/a/45145800/3832970). – Wiktor Stribiżew Mar 19 '20 at 17:04
re.sub(r'((?<!\S)[$#a-zA-Z0-9_]{1,})(\s{1,}\1\b)+', '\\1', "removing #redund$ant #redund$ant #redund$ant") – Cobry Mar 19 '20 at 17:05
1

If your boundaries are whitespace ones, use `(?<!\S)...(?!\S)`. – Wiktor Stribiżew Mar 19 '20 at 17:06
thank you :) after reading your answer 100 times i understood it a bit :) – Cobry Mar 19 '20 at 17:07
1

I suggest you should make a break for a half an hour, mediate a bit and re-read. All should be clear. Please drop a comment if anything is not. – Wiktor Stribiżew Mar 19 '20 at 17:08

python regex replace redundant words with special characters

0 Answers0