python 构造三维全零数组

temp1 = [[] for i in range(10)]
temp2 = [temp1 for i in range(20)]
temp3 = [temp2 for i in range(30)]
for i in range(30):
    for j in range(20):
        for k in range(10):
            temp3[i][j][k] = 0

但是赋值的时候还是发现是指向同一地址的
所以还得这样

matrix3d=[]
for i in range(30):
    matrix3d.append([])
    for j in range(20):
        matrix3d[i].append([])
        for k in range(10):
            matrix3d[i][j].append(0)