Comparison of variable swapping in Python

>>> import dis
>>> dis.dis(idiomatic_swap)
  2           0 LOAD_FAST                0 (a)
              3 LOAD_FAST                1 (b)
              6 ROT_TWO
              7 STORE_FAST               1 (b)
             10 STORE_FAST               0 (a)
             13 LOAD_CONST               0 (None)
             16 RETURN_VALUE
>>>
>>>
>>> def subtraction_swap(a, b):
...     a = a + b
...     b = a - b
...     a = a - b
...
>>>
>>> def xor_swap(a, b):
...     a = a ^ b
...     b = a ^ b
...     a = a ^ b
...
>>>
>>> from timeit import Timer
>>>
>>> def do_test(n, func_name):
...     t = Timer('f(1,2)', 'from __main__ import %s as f' % func_name)
...     print t.timeit(number=n)
...
>>> do_test(1000000, 'idiomatic_swap')
0.273808002472
>>> do_test(1000000, 'subtraction_swap')
0.422091960907
>>> do_test(1000000, 'xor_swap')
0.501079797745
>>>