异常处理

data = {‘name‘:‘ABCD‘,
        ‘age‘:22}
aa = [1,2,3,4]
try:
    data[‘naaa‘]
    aa[5]

# except (KeyError,IndexError) as e:
#     print()   #当出现错误后处理方法一样，可以用这种方法
#------分别抓取错误----
# except KeyError as e:
#     print("the key is error",e)
# except IndexError as e:
#     print("the index ",e)
except Exception as e:
    print("出错了",e)    # 能基本抓住所有错误，常用第二种方法

data = {‘name‘:‘ABCD‘,
        ‘age‘:22}
aa = [1,2,3,4]
try:
    # data[‘naaa‘]
    aa[2]

except KeyError as e:
    print("the key is error",e)
except IndexError as e:
    print("the index ",e)
except Exception as e:
    print("未知错误",e)
else:
    print("else，如果没有错，执行")
finally:
    print("finally不管有没有错，都执行")

# else，如果没有错，执行
# finally不管有没有错，都执行

class ABCException(Exception):
    def __init__(self,msg):
        self.msg = msg

    def __str__(self):   # __str__ 可以自定义，也可以不写使用基类的
        return self.msg

try:
    raise ABCException("自己写的异常")    #自己写的异常需要自己触发
except ABCException as e:
    print(e)