Python实现三个数能组成多少个三位数

b=[1,2,3,4]
print(b[1])
for i in range(len(b)):
    for j in range(len(b)):
        for k in range(len(b)):
            if b[i]!=b[j] and b[i] != b[k] and b[j] !=b[k]:
                print(b[i],b[j],b[k])