xkumiyu

# for _ in range(N)
for _ in range(N):
    pass

# for i in range(N)
for i in range(N):
    i

# while i < N
i = 0

xkumiyu

# [None] * N
[None] * N

# [None for _ in range(N)]
[None for _ in range(N)]

xkumiyu

# faster
[[None] * N for _ in range(N)]

# slower
[[None for _ in range(N)] for _ in range(N)]

# NG
[[None] * N] * N

xkumiyu

# for i in range(len(A))
for i in range(len(A)):
    A[i]

# for a in A
for a in A:
    a

xkumiyu

# append()
A = []
for i in range(N):
    A.append(i)

# A[i] = i, assignment
A = [None] * N
for i in range(N):
    A[i] = i