Python efficiency of and vs multiple ifs

Question

Is there an efficiency difference between using and in an if statement and using multiple if statements? In other words, is something like

if expr1 == expr2 and         


        

Answer 1

The first one (one if with and) is faster :-)

I tried it out using timeit. These are the results:

Variant 1: 9.82836714316
Variant 2: 9.83886494559
Variant 1 (True): 9.66493159804
Variant 2 (True): 10.0392633241

For the last two, the first comparision is True, so the second one is skipped. Interesting results.

---

import timeit


print "Variant 1: %s" % timeit.timeit("""
for i in xrange(1000):
    if i == 2*i and i == 3*i:
        pass
        """,
        number = 1000)

print "Variant 2: %s" % timeit.timeit("""
for i in xrange(1000):
    if i == 2*i:
        if i == 3*i:
            pass
        """,
        number = 1000)

print "Variant 1 (True): %s" % timeit.timeit("""
for i in xrange(1000):
    if i == i and i == 3*i:
        pass
        """,
        number = 1000)

print "Variant 2 (True): %s" % timeit.timeit("""
for i in xrange(1000):
    if i == i:
        if i == 3*i:
            pass
        """,
        number = 1000)