Question

i need to find and replace patterns in a string with a dynamically generated content.

lets say i want to find all strings within ” in the string and double the string.
a string like:

my 'cat' is 'white' should become my 'catcat' is 'whitewhite'

all matches could also appear twice in the string.

thank you

Answer 1

Make use of the power of regular expressions. In this particular case:

import re

s = "my 'cat' is 'white'"

print re.sub("'([^']+)'", r"'\1\1'", s) # prints my 'catcat' is 'whitewhite'

\1 refers to the first group in the regex (called $1 in some other implementations).