argmax.py

#!/usr/bin/env python
from __future__ import division

from random import random
from timeit import timeit

def maxarg(arr):
    counter = 0
    arg = 0
    m = arr[0]
    for x in arr:
        if x > m:
            m = x
            arg = counter
        counter += 1
    return arg

a = [random() for i in range(10000000)]

print timeit('a.index(max(a))', 'from __main__ import a', number=3)
print timeit('maxarg(a)', 'from __main__ import a, maxarg', number=3)