Python：编写代码生成列表 [[0, 0, 0, 0, 0]

# 写法1
 ret = []
 for i in range(4):
     l1 = [0, ]
     for j in range(4):
         l1.append(l1[-1]+i)
     ret.append(l1)
 print(ret)

# 写法2
ret = []
for i in range(4):
    l1 = []
    for j in range(5):
        l1.append(i*j)
    ret.append(l1)
print(ret)

#写法3：列表推导式
ret = [[i * j for j in range(5)] for i in range(4)]
print(ret)


#写法4
ret = []
for i in range(4):
    ret.append(list(map(lambda x: x*i, [0, 1, 2, 3, 4])))
print(ret)