-- coding: utf-8 --

def findMinAndMax(L):

if(len(L) == 0):
    return (None,None)
max = L[0]
min = L[0]
for num in L :
    if(num < min):
        min = num 
    if(num > max):
        max = num 
return (min, max)

测试

if findMinAndMax([]) != (None, None): print('测试失败!') elif findMinAndMax([7]) != (7, 7): print('测试失败!') elif findMinAndMax([7, 1]) != (1, 7): print('测试失败!') elif findMinAndMax([7, 1, 3, 9, 5]) != (1, 9): print('测试失败!') else: print('测试成功!')