I want to replace letters/words, but I am facing challenges in one aspect of my code

I will be using lloll as an example word.

Here’s my code:

mapping = {'ll':'o','o':'ll'}
string = 'lloll'
out = ' '.join(mapping.get(s,s) for s in string.split())
print(out)

The output should be ollo, but I get lloll. When I write ll o ll, it works, but I don’t want spaces in between the ll and the o, and I don’t want to do something like mapping = {'lloll':'ollo'}.

>Solution :

Not sure if this accounts for all edge cases (what about overlapping matches?), but my current idea is to re.split the string by the mapping’s keys and then apply the mapping.

import re
mapping = {'ll':'o','o':'ll'}
string = 'lloll'
choices = f'({"|".join(mapping)})'
result = ''.join(mapping.get(s, s) for s in re.split(choices, string))