Python re.sub(): how to substitute all 'u' or 'U's with 'you'

Question

I am doing some text normalization using python and regular expressions. I would like to substitute all \'u\'or \'U\'s with \'you\'. Here is what I have done so far:

Answer 1

Use a special character \b, which matches empty string at the beginning or at the end of a word:

print re.sub(r'\b[uU]\b', 'you', text)

spaces are not a reliable solution because there are also plenty of other punctuation marks, so an abstract character \b was invented to indicate a word's beginning or end.