列表推导式

a = [x for x in range(4)]

# 可以看做
a = []
for x in range(4):
    a.append(x)

a = [x for x in range(3, 10) if x % 2 == 0]

# 可以看做
a = []
for x in range(3, 10):
    if x % 2 == 0:
        a.append(x)

a = [(x, y) for x in range(1, 3) for y in range(3)]

# 可以看做
a = []
for x in range(1, 3):
    for y in range(3):
        a.append((x, y))

a = [(x, y) for x in range(1, 3) for y in range(3) for z in range(4, 6)]

# 可以看做
a = []
for x in range(1, 3):
    for y in range(3):
        for z in range(4, 6):
            a.append((x, y, z))