iteration speed tests

output

❯ ./speedtest.sh
2 ** 10 items
2 slices: 10000 loops, best of 3: 106 usec per loop
0 slices: 10000 loops, best of 3: 151 usec per loop

2 ** 15 items
2 slices: 100 loops, best of 3: 4.23 msec per loop
0 slices: 100 loops, best of 3: 5.68 msec per loop

output (no identity comparisons)

❯ ./speedtest.sh
2 ** 10 items
2 slices: 10000 loops, best of 3: 109 usec per loop
0 slices: 10000 loops, best of 3: 123 usec per loop

2 ** 15 items
2 slices: 100 loops, best of 3: 4.48 msec per loop
0 slices: 100 loops, best of 3: 5.2 msec per loop

speedtest.py

from __future__ import print_function

def pairs_2(xs):
    for p in zip(xs[:-1], xs[1:]): 
        yield p

def pairs_0(lst):
    last = object()
    dummy = last
    for x in lst:
        if last is not dummy:
            yield last,x
        last = x

d = {2: pairs_2, 0: pairs_0}

def test(i, n, w):
    r = range(2 ** n)
    if w is list:
        r = list(r)
    big_list = list(d[i](r))

speedtest.sh

#!/usr/bin/env bash
echo '2 ** 10 items'
echo -n '2 slices: '
python -m timeit -s'import speedtest' 'speedtest.test(2, 10, None)'
echo -n '0 slices: '
python -m timeit -s'import speedtest' 'speedtest.test(0, 10, None)'
echo

echo '2 ** 15 items'
echo -n '2 slices: '
python -m timeit -s'import speedtest' 'speedtest.test(2, 15, None)'
echo -n '0 slices: '
python -m timeit -s'import speedtest' 'speedtest.test(0, 15, None)'