Python List Allocation

main.py

from dataclasses import dataclass
from functools import wraps
from time import time


@dataclass
class Thing:
    pass


def timed(f):
    @wraps(f)
    def wrap(*args, **kw):
        ts = time()
        result = f(*args, **kw)
        te = time()
        print(f'func:{f.__name__} args:[{args}, {kw}] took: {te-ts:.08f} sec')
        return result
    return wrap


@timed
def create_matrix(width, height):
    result = []

    for _ in range(height):
        for _ in range(width):
            result.append(Thing())

    return result


@timed
def create_matrix_with_listcomp(width, height):
    return [[Thing() for _ in range(width)] for _ in range(height)]


@timed
def create_prealloc_matrix(width, height):
    result = [None] * height
    for j in range(height):
        result[j] = [None] * width

    for j in range(height):
        for i in range(width):
            result[j][i] = Thing()

    return result


@timed
def create_array(width, height):
    result = []

    for _ in range(width*height):
        result.append(Thing())

    return result


@timed
def create_array_with_listcomp(width, height):
    return [Thing() for _ in range(width*height)]


@timed
def create_prealloc_array(width, height):
    result = [None] * width * height

    for i in range(width * height):
        result[i] = Thing()

    return result


def main():
    create_matrix(100, 100)
    create_matrix_with_listcomp(100, 100)
    create_prealloc_matrix(100, 100)
    create_array(100, 100)
    create_array_with_listcomp(100, 100)
    create_prealloc_array(100, 100)

if __name__ == '__main__':
    main()

result.txt

func:create_matrix args:[(100, 100), {}] took: 0.00401878 sec
func:create_matrix_with_listcomp args:[(100, 100), {}] took: 0.00277829 sec
func:create_prealloc_matrix args:[(100, 100), {}] took: 0.00284767 sec
func:create_array args:[(100, 100), {}] took: 0.00486350 sec
func:create_array_with_listcomp args:[(100, 100), {}] took: 0.00380182 sec
func:create_prealloc_array args:[(100, 100), {}] took: 0.00343609 sec