我想要輸出None而不是0

Question

def second_largest(numbers):
    first, second = 0,0
    for n in numbers:
        if n > first:
            first, second = n, first
        elif first > n > second:
            second = n
    return second
print(second_largest([2,2,2]))

如果沒有第二大數字並且也有空列表，我想輸出None不為0。

Answer 1

嘗試更改返回行以return second or None 。

Answer 2

在return語句中稍作調整即可。 查看以下代碼：

def second_largest(numbers):
    first, second = 0,0
    for n in numbers:
        if n > first:
            first, second = n, first
        elif first > n > second:
            second = n
    return None if second ==0 else second
print(second_largest([2,2,2]))