Question

Basically, the reverse of this. Here’s my attempt, but it’s not working.

def titlecase(value):
    s1 = re.sub('(_)([a-z][A-Z][0-9]+)', r'\2'.upper(), value)
    return s1

Answer 1

def titlecase(value):
    return "".join(word.title() for word in value.split("_"))

Python is more readable than regex, and easier to fix when it’s not doing what you want.

If you want the first letter lowercase as well, I would use a second function that calls the function above to do most of the work, then just lowercases the first letter:

def titlecase2(value):
     return value[:1].lower() + titlecase(value)[1:]