ewok ewok - 1 year ago 84
Python Question

Python: if any strings in a list match regex

I need to check if any of the strings in a list match a regex. If any do, I want to continue. The way I've always done it in the past is using list comprehension with something like:

r = re.compile('.*search.*')
if [line for line in output if r.match(line)]:

Which I now realize is pretty inefficient. If the very first item in the list matches, we can skip all the rest of the comparisons and move on. I could improve this with:

r = re.compile('.*search.*')
for line in output:
if r.match(line):

But I'm wondering if there's a more pythonic way to do this.

Answer Source

You can use the builtin any():

if any(re.match(line) for line in output):

Passing in the lazy generator to any() will allow it to exit on the first match without having to check any farther into the iterable.