index_benchmark.py

from timeit import timeit

children = range(1, 1000)
number = 10000

def indexof(x):
    for i in range(len(children)):
        if children[i] is x:
            return i

    return -1

def index(x):
    try:
        return children.index(x)
    except ValueError:
        return -1

if __name__ == '__main__':
    print("indexof(200) = {}\nindexof(2000) = {}\n".format(
        indexof(200), indexof(2000)))
    print("result of calling {} times:".format(number))
    print(timeit(
        "indexof(200); indexof(2000)", 
        number=number, 
        setup="from __main__ import indexof"))

    print("index(200) = {}\nindex(2000) = {}\n".format(
        indexof(200), indexof(2000)))
    print("result of calling {} times:".format(number))
    print(timeit(
        "index(200); index(2000)", 
        number=number, 
        setup="from __main__ import index"))

""" Results:

    Python 2:
        indexof(200) = 199
        indexof(2000) = -1

        result of calling 10000 times:
        0.784973859787

        index(200) = 199
        index(2000) = -1

        result of calling 10000 times:
        0.238559007645

    Python 3:
        indexof(200) = 199
        indexof(2000) = -1

        result of calling 10000 times:
        2.492364877994987

        index(200) = 199
        index(2000) = -1

        result of calling 10000 times:
        0.015736084009404294
"""