python实现列表中最大最小值输出的示例

def findMinAndMax(L):  maxL = None  minL = None  if L:    maxL = L[0]    minL = L[0]    for i in range(len(L)):      if L[i] > maxL:        maxL = L[i]      elif L[i] < minL:        minL = L[i]  else:    maxL = None    minL = None  return (minL, maxL)

# 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!')