Slow lists, Fast list (python 3)

python_list_bench.py

import timeit

INNER_ITERATIONS = 10000
TIMEIT_ITERATIONS = 5000


def func():
    return [x for x in range(INNER_ITERATIONS)]


def func2():
    return list(range(INNER_ITERATIONS))


def func3():
    res = []

    for x in range(INNER_ITERATIONS):
        res.append(x)

    return res


def func4():
    return list(x for x in range(INNER_ITERATIONS))


def func5():
    return [*range(INNER_ITERATIONS)]


assert func() == func2() == func3() == func4() == func5()

for f in (func, func2, func3, func4, func5):
    print('{}: {}'.format(f.__name__, timeit.timeit(f, number=TIMEIT_ITERATIONS)))

# func: 1.9709388579940423
# func2: 1.1561449829969206
# func3: 4.777506334001373
# func4: 3.2804647559969453
# func5: 1.1617357560025994