How to replace an re match with a transformation of that match?

Question

For example, I have a string:

The struct-of-application and struct-of-world

With re.sub

Answer 1

Use a function for the replacement

s = 'The struct-of-application and struct-of-world'
p = re.compile('((\w+-)+\w+)')
def replace(match):
    return 'http://{}'.format(match.group())
    #for python 3.6+ ... 
    #return f'http://{match.group()}'

>>> p.sub(replace, s)

'The http://struct-of-application and http://struct-of-world'
>>>