Digit sum speed tests

sum_digits_speed_test.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

''' Sum the digits of a non-negative integer

    Speed tests of various implementations

    Written by PM 2Ring & hiro protagonist 2016.12.19

    sum_digits_hiro is faster than sum_digits_pm_map until digits=20 
    in Python 3.6 and digits=60 in Python 2.6
    For large numbers of digits, sum_digits_pm_dict is the fastest
'''

from __future__ import print_function, division
from timeit import Timer

def sum_digits_hiro(n):
    count = 0
    while n:
        count += n % 10
        n //= 10
    return count

def sum_digits_pm_gen(n):
    return sum(int(d) for d in str(n))

def sum_digits_pm_map(n):
    return sum(map(int, str(n)))

def sum_digits_pm_ord(n):
    return sum(ord(d)-48 for d in str(n))

def sum_digits_pm_dict(n, 
    digit={'0':0,'1':1,'2':2,'3':3,'4':4,'5':5,'6':6,'7':7,'8':8,'9':9}):
    return sum(digit[d] for d in str(n))


funcs = (
    sum_digits_hiro,
    sum_digits_pm_gen,
    sum_digits_pm_map,
    sum_digits_pm_ord,
    sum_digits_pm_dict,
)

def verify():
    results = [[func(n) for n in data] for func in funcs]
    func = funcs[0]
    first = [func(n) for n in data]
    print(all(first == [func(n) for n in data] for func in funcs[1:]))

def time_test(loops, reps):
    ''' Print timing stats for all the functions '''
    timings = []
    for func in funcs:
        fname = func.__name__
        setup = 'from __main__ import data, ' + fname
        cmd = 'for n in data: {0}(n)'.format(fname)
        t = Timer(cmd, setup)
        result = t.repeat(reps, loops)
        result.sort()
        timings.append((result, fname))

    timings.sort()
    for result, fname in timings:
        print('{0:18} {1}'.format(fname, result))


digits = 20
lo = 10**(digits-1)
print('digits:', digits)
data = range(lo, lo + 1000)

#verify()
time_test(loops=20, reps=3)