python - regex to remove a if it occures after a b

Question

I want to remove all the dots in a text that appear after a vowel character. how can I do that?

Here is the code I wish I had:

string = re.sub('[aeuio]\.', '[aeuio]', string)

Meaning like keep whatever vowel you have matched and remove the '.' next to it.

Answer 1

Capture the vowel and replace with a backreference to it:

import re
s = "Se.hi.mo."
s = re.sub(r'([aeuio])\.', r'\1', s)
print(s) # => Sehimo

See the Python demo and a regex demo.

Here, ([aeuio]) forms a capturing group and \1 in the replacement pattern is a numbered backreference referencing the text captured into Group 1.

Mind the usage of raw string literals where a backslash does not form an escape sequence: r'\1' = '\\1'.