What's a faster operation, re.match/search or str.find?
The question: which is faster is best answered by using timeit
.
from timeit import timeit
import re
def find(string, text):
if string.find(text) > -1:
pass
def re_find(string, text):
if re.match(text, string):
pass
def best_find(string, text):
if text in string:
pass
print timeit("find(string, text)", "from __main__ import find; string='lookforme'; text='look'")
print timeit("re_find(string, text)", "from __main__ import re_find; string='lookforme'; text='look'")
print timeit("best_find(string, text)", "from __main__ import best_find; string='lookforme'; text='look'")
The output is:
0.441393852234
2.12302494049
0.251421928406
So not only should you use the in
operator because it is easier to read, but because it is faster also.
Use this:
if 'lookforme' in s:
do something
Regex need to be compiled first, which adds some overhead. Python's normal string search is very efficient anyways.
If you search the same term a lot or when you do something more complex then regex become more useful.
re.compile speeds up regexs a lot if you are searching for the same thing over and over. But I just got a huge speedup by using "in" to cull out bad cases before I match. Anecdotal, I know. ~Ben