Python: how to substitute and know whether it matched

Question

I know that re.sub(pattern, repl,text) can substitute when pattern matches, and then return the substitute.

My code is:

text = re.sub(p         


        

Answer 1

Use re.subn

Perform the same operation as sub(), but return a tuple (new_string, number_of_subs_made).

and then check the number of replacements that were made. For example:

text2, numReplacements = re.subn(pattern, repl, text1)
if numReplacements:
    # did match
else:
    # did not match