python练习三

题目：请使用迭代查找一个list中最小和最大值，并返回一个tuple

环境：windows 7+anaconda3 64bit+pycharm

def findMinAndMax(L):

    if L!=[]:

        (min,max)=(L[0],L[0])

        for x in L:

            if max<x:

                max=x

            if min>x:

                min=x

        return (min,max)

    else:

        return (None,None)

print(findMinAndMax([1,3,5,7,9]))

print(findMinAndMax([]))

print(findMinAndMax([1]))

输出结果：

(1, 9)

(None, None)

(1, 1)