我想要输出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]))

I want to output by None not 0 if there is no second largest number and also if there is empty list.

Answer 1

尝试更改返回行以return second or None 。

Answer 2

A little tweak in return statement will do. Check out the below code:

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]))