python - 如何使用 range(len(list)) 查找列表中所有偶数索引整数的乘积？

Question

我是编码的新手，我正在做一项作业，我必须在一个巨大的列表中找到所有索引为偶数的整数的乘积:

number_list = [12, 41, 10, 34, 37, 2, 3, 8, 42, 46, 46, 27, 13, 49, 41, 2, 28, 21, 37, 27, 31, 19, 46, 7, 50, 1, 46, 45, 19, 10, 14, 8, 44, 14, 10, 4, 23, 29, 46, 18, 32, 40, 32, 7, 33, 45, 26, 24, 43, 45]

问题建议使用 range(len(list))，它给了我范围 (1,50)，但我不明白这有什么关系。我设法在不使用该方法的情况下得到了答案:

number_list = [12, 41, 10, 34, 37, 2, 3, 8, 42, 46, 46, 27, 13, 49, 41, 2, 28, 21, 37, 27, 31, 19, 46, 7, 50, 1, 46, 45, 19, 10, 14, 8, 44, 14, 10, 4, 23, 29, 46, 18, 32, 40, 32, 7, 33, 45, 26, 24, 43, 45]

result = 1
evenlist = number_list[::2]
for num in evenlist:
    result = result * num

range(len(list)) 在这里有什么用？

Answer 1

可能是这样的，你用数组的索引来引用它；

number_list = [12, 41, 10, 34, 37, 2, 3, 8, 42, 46, 46, 27, 13, 49, 41, 2, 28, 21, 37, 27, 31, 19, 46, 7, 50, 1, 46, 45, 19, 10, 14, 8, 44, 14, 10, 4, 23, 29, 46, 18, 32, 40, 32, 7, 33, 45, 26, 24, 43, 45]

result = 1
for idx in range(0, len(number_list), 2):
   result = result * number_list[idx]