20-异常处理

def test():
    print(‘test running‘)
choice_dic={
    ‘1‘:test
}
while True:
    choice=input(‘>>: ‘).strip()
    if not choice or choice not in choice_dic:continue #这便是一种异常处理机制啊
    choice_dic[choice]()

try:
    被检测的代码块
except 异常类型:
    try中一旦检测到指定的异常类型,则执行此位置的逻辑代码

s1 = ‘hello‘
try:
   int(s1)
except IndexError as e:
   print(e)
运行结果:
Traceback (most recent call last):
  File "J:/Python_Project/day09/练习/123.py", line 77, in <module>
    int(s1)
ValueError: invalid literal for int() with base 10: ‘hello‘

s1 = ‘hello‘
try:
    int(s1)
except IndexError as e:
    print(e)
except KeyError as e:
    print(e)
except ValueError as e:
    print(e)
#except Exception as e:
#    print(e)
else:
    print(‘try内代码块没有异常则执行我‘)
finally:
    print(‘无论异常与否,都会执行该模块,通常是进行清理工作‘)

#_*_coding:utf-8_*_

try:
    raise TypeError(‘类型错误‘)
except Exception as e:
    print(e)
运行结果:
类型错误

#_*_coding:utf-8_*_
__author__ = ‘Linhaifeng‘

class EgonException(BaseException):
    def __init__(self,msg):
        self.msg=msg
    def __str__(self):
        return self.msg

try:
    raise EgonException(‘类型错误‘)
except EgonException as e:
    print(e)