Comparison of performance of python lists and sets

intersect.py

# Compare the performance of python lists and sets when doing
# intersections.
#
# No real surprises here. Sets are faster than lists, and generating
# sets on-the-fly from lists is slightly slower than using sets to
# begin with.

import timeit
import random

def create_ints(n, beg, end):
    ints = []
    while len(ints) < n:
        r = random.randint(beg, end)
        if not r in ints:
            ints.append(r)
    return ints

list1 = create_ints(10000, 10000, 99999)
list2 = create_ints(1000, 10000, 99999)

set1 = set(list1)
set2 = set(list2)

def intersect_using_lists():
    intersect = []
    for i in list1:
      if i in list2:
        intersect.append(i)
    return intersect

def intersect_using_comp():
    intersect = [i for i in list1 if i in list2]
    return intersect

def intersect_using_precreated_sets():
    intersect = set1.intersection(set2)
    return intersect

def intersect_using_sets():
    intersect = set(list1).intersection(set(list2))
    return intersect

for fn in [intersect_using_lists,
           intersect_using_comp,
           intersect_using_precreated_sets,
           intersect_using_sets]:
    fn_name = fn.__name__
    print "Running %s" % (fn_name,)
    print timeit.timeit(stmt="%s()" % (fn_name,), setup="from __main__ import %s" % (fn_name,), number=100)