Compare the speed of zip with various Numpy stack functions

zip_vs_stack_speed_test.py

#!/usr/bin/env python3

''' Compare the speeds of zip and various Numpy functions
    for stacking to 1D Numpy arrays into a 2D array

    See https://stackoverflow.com/q/44409084/4014959

    Written by PM 2Ring 2017.06.08
'''

import numpy as np
from timeit import Timer

cmds = {
    'column': 'np.column_stack((a, b))',
    'dstack': 'np.dstack((a, b))',
    'stack': 'np.stack((a, b), axis=-1)',
    'zip': 'np.array(list(zip(a, b)))',
}

loops = 1000
setup = 'from __main__ import np, a, b'

for i in range(10):
    n = 1 << i
    a = np.arange(1, n + 1)
    b = np.arange(n + 1, 2*n + 1)
    print('\nSize:', n)

    timings = []
    for name, cmd in cmds.items():
        t = Timer(cmd, setup)
        result = sorted(t.repeat(3, loops))
        timings.append((result, name))
    timings.sort()
    for result, name in timings:
        print('{:<6} : {}'.format(name, result))