Code to check the prefix character in string in python

Question

I wonder what is the corresponding code for the following code in python. I want to check the charactares backword in a string. An exampel if I have a str="anything" and i want to add a '2' if the character is vowel and if the prefix is vowel and suffix is vowel so I want to add '2ä before and after the charctar so the result will be str="a0n0y0th0i0ng". I hope that I could clarify it as much as possible. In c++ we can write str.back(), is there anything like this in python?

Answer 1

You can use regex replacement.

import re

my_str = 'anything'
output = re.sub(r'([aeiouy])', r'0\g<1>0, my_str)
# '0a0n0y0th0i0ng'

You could follow that up with, say, output.strip('0') to get rid of the character at the front if you really don't want it there.

re.sub() takes a regex as its first argument (we submit a capture group for a single letter, which can be any vowel), and the replacement as the second argument. The replacement in this case, r'0\g<1>0, literally means to insert 0, then the captured group 1 (which is the vowel), then another 0 (see this answer for more details).