class ShortInputException(Exception):
    def __init__(self, length, atleast):
        self.length = length
        self.atleast = atleast
def main():
    try:
        s = input('請(qǐng)輸入 --> ')
        if len(s) < 3:
            # raise引發(fā)一個(gè)你定義的異常
            raise ShortInputException(len(s), 3)
    except ShortInputException as result:#x這個(gè)變量被綁定到了錯(cuò)誤的實(shí)例
        print('ShortInputException: 輸入的長(zhǎng)度是 %d,長(zhǎng)度至少應(yīng)是 %d'% (result.length, result.atleast))
    else:
        print('沒有異常發(fā)生')
main()

#1.用戶自定義異常類型，只要該類繼承了Exception類即可，至于類的主題內(nèi)容用戶自定義，可參考官方異常類
class TooLongExceptin(Exception):
  "this is user's Exception for check the length of name "
  def __init__(self,leng):
    self.leng = leng
  def __str__(self):
    print("姓名長(zhǎng)度是"+str(self.leng)+"，超過長(zhǎng)度了")

 #1.捕捉用戶手動(dòng)拋出的異常，跟捕捉系統(tǒng)異常方式一樣
def name_Test():
  try:
    name = input("enter your naem:")
    if len(name)>4:
      raise TooLongExceptin(len(name))
    else :
      print(name)
 
  except TooLongExceptin,e_result: #這里異常類型是用戶自定義的
    print("捕捉到異常了")
    print("打印異常信息：",e_result)
 
#調(diào)用函數(shù)，執(zhí)行
name_Test()
==========執(zhí)行結(jié)果如下：==================================================
enter your naem:aaafsdf
捕捉到異常了
Traceback (most recent call last):
打印異常信息： 姓名長(zhǎng)度是7，超過長(zhǎng)度了
姓名長(zhǎng)度是7，超過長(zhǎng)度了
 File "D:/pythoyworkspace/file_demo/Class_Demo/extion_demo.py", line 16, in name_Test
  raise TooLongExceptin(len(name))
__main__.TooLongExceptin: <exception str() failed>
 
During handling of the above exception, another exception occurred:
 
Traceback (most recent call last):
 File "D:/pythoyworkspace/file_demo/Class_Demo/extion_demo.py", line 26, in <module>
  name_Test()
 File "D:/pythoyworkspace/file_demo/Class_Demo/extion_demo.py", line 22, in name_Test
  print("打印異常信息：",e_result)
TypeError: __str__ returned non-string (type NoneType)