No9：Python的try捕获异常

1、演示用法

try:
    # 主代码块
    pass
except KeyError as e:
    # 异常时，执行该块
    pass
else:
    # 主代码块执行完，执行该块
    pass
finally:
    # 无论异常与否，最终执行该块
    pass

2、捕获异常

• 单个异常

try:
    int("error")
except Exception as e:
    print(e)

• 多个异常

try:
    int("error")
except IndexError as e:
    print(e)
except KeyError as e:
    print(e)
except ValueError as e:
    print(e)

• 先定义特殊提醒的异常，最后定义Exception，来确保程序正常运行并捕获所有异常

try:
    int("error"
except KeyError as e:
    print(e)
except Exception as e:
    print(e)