python 1，2，3，4，5这五个数字可以组成多少个不重复的三位数，请用一个列表把所有可能枚举出来

可以使用嵌套循环来实现。外层循环遍历百位数字，中间循环遍历十位数字，内层循环遍历个位数字。然后将三个数字组合成一个三位数，加入到列表中。代码如下：

numbers = [1, 2, 3, 4, 5]
result = []

for i in numbers:
    for j in numbers:
        for k in numbers:
            if i != j and j != k and i != k:
                num = i * 100 + j * 10 + k
                result.append(num)

print(result)

输出结果：

[123, 124, 125, 132, 134, 135, 142, 143, 145, 152, 153, 154, 213, 214, 215, 231, 234, 235, 241, 243, 245, 251, 253, 254, 312, 314, 315, 321, 324, 325, 341, 342, 345, 351, 352, 354, 412, 413, 415, 421, 423, 425, 431, 432, 435, 451, 452, 453, 512, 513, 514, 521, 523, 524, 531, 532, 534, 541, 542, 543]