异常时程序发生错误的信号,一旦程序出错机会产生一种类型的异常,
为了保证程序的健壮性
语法错误:程序运行前就应该解决
逻辑错误:try…except
异常处理一:
try: print(x) print('hello') l=[1,2,3] l=[0] except NameErroras e: print('按照这个方法处理') print('other code...')
异常处理二:
try: # print(x) print('hello') l=[1,2,3] l=[0] dic={'x':111} dic['e'] except NameErroras e: print('按照这个方法处理') except IndexErroras e: print('index error') except KeyErroras e: print('key error')
异常处理三:
try: # print(x) print('hello') l=[1,2,3] l=[0] dic={'x':111} dic['e'] except (NameError,IndexError,KeyError)as e: print(e)
异常处理四:
try: # print(x) print('hello') l=[1,2,3] l=[0] dic={'x':111} dic['e'] except Exceptionas e: print(e)
异常处理五:
try: # print(x) print('hello') l=[1,2,3] l=[0] dic={'x':111} dic['e'] except NameErroras e: print('name error') except IndexErroras e: print('index error') except Exceptionas e: print(e)
异常处理六:
try: # print(x) print('hello') l=[1,2,3] l=[0] dic={'x':111} dic['e'] except NameErroras e: print('name error') except IndexErroras e: print('index error') except Exceptionas e: print(e) else: print('当被检测代码块没有异常时执行') finally: 回收系统资源