import timeit
malist = ['abc123'] + ['xcv123']*1000

timeit.timeit('[s for s in malist if sub in s]', setup='from __main__ import malist, sub', number=100000)
3.1818524750124197

timeit.timeit('next((s for s in malist if sub in s), None)', setup='from __main__ import malist, sub', number=100000)
0.042908454008284025

sub = set(['test1'])
p = r'c:\users\foler\test1'
parts = set(p.split(r'\'))
if sub.inersection(parts):
    do stuff