Number of regex matches

user_197657 0
Viewed 119931

I'm using the finditer function in the re module to match some things and everything is working.

Now I need to find out how many matches I've got. Is it possible without looping through the iterator twice? (one to find out the count and then the real iteration)

Some code:

imageMatches = re.finditer("<img src\=\"(?P<path>[-/\w\.]+)\"", response[2])
# <Here I need to get the number of matches>
for imageMatch in imageMatches:
    doStuff

Everything works, I just need to get the number of matches before the loop.

python regex
7 Answers

I know this is a little old, but this but here is a concise function for counting regex patterns.

def regex_cnt(string, pattern):
    return len(re.findall(pattern, string))

string = 'abc123'

regex_cnt(string, '[0-9]')
user_101005450

For those moments when you really want to avoid building lists:

import re
import operator
from functools import reduce
count = reduce(operator.add, (1 for _ in re.finditer(my_pattern, my_string)))

Sometimes you might need to operate on huge strings. This might help.

user_48715800

if you are using finditer method best way you can count the matches is to initialize a counter and increment it with each match

user_190440150
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