Question

Ok say I have a string in python:

str="martin added 1 new photo to the <a href=''>martins photos</a> album."

the string contains a lot more css/html in real world use

What is the fastest way to change the 1 ('1 new photo') to say '2 new photos'. of course later the '1' may say '12'.
Note, I don’t know what the number is, so doing a replace is not acceptable.
I also need to change 'photo' to 'photos' but I can just do a .replace(...).
Unless there is a neater, easier solution to modify both?

Answer 1

It sounds like this is what you want (although why is another question :^)

import re

def add_photos(s,n):
    def helper(m):
        num = int(m.group(1)) + n
        plural = '' if num == 1 else 's'
        return 'added %d new photo%s' % (num,plural)
    return re.sub(r'added (\d+) new photo(s?)',helper,s)

s = "martin added 0 new photos to the <a href=''>martins photos</a> album."
s = add_photos(s,1)
print s
s = add_photos(s,5)
print s
s = add_photos(s,7)
print s

Output

martin added 1 new photo to the <a href=''>martins photos</a> album.
martin added 6 new photos to the <a href=''>martins photos</a> album.
martin added 13 new photos to the <a href=''>martins photos</a> album.