forループ（forloops）

Regular loop

e = []
for i in range(11):
  e.append(i**2)
e

[0, 1, 4, 9, 16, 25, 36, 49, 64, 81, 100]

リストによるforループ（List loop）

e2 = ['A', 'B', 'C', 'D']
for item in e2:
    print(item,end=' ')

A B C D

リスト内包ループ（List comprehension loop）

e3 = [i**5 for i in range(11)]
e3

[0, 1, 32, 243, 1024, 3125, 7776, 16807, 32768, 59049, 100000]

[i**5 for i in range(11)]

[0, 1, 32, 243, 1024, 3125, 7776, 16807, 32768, 59049, 100000]

Double forloop

import numpy as np
import time

start_time = time.perf_counter()
nn = 1001
f = np.empty((nn,nn))
for i in range(nn):
    for j in range(nn):
        f[i,j] = i*j
end_time = time.perf_counter()
print(end_time - start_time)

0.1951509800000082