Python内置的处理异常机制与调试

try:  #先执行 可能会发生错误的代码
    print(‘try...‘)
    r = 10 / int(‘2‘)
    print(‘result:‘, r)
except ValueError as e:  捕捉 异常的类型 并进行修饰
    print(‘ValueError:‘, e)
except ZeroDivisionError as e:
    print(‘ZeroDivisionError:‘, e)
else:  #当没有错误发生时 都会执行这段代码卡
    print(‘no error!‘)
finally:  # 无论有没有 错误 流程体结束都会执行 finally
    print(‘finally...‘)
print(‘END‘)

def foo(s):
    return 10 / int(s)

def bar(s):
    return foo(s) * 2

def main():
    try:
        bar(‘0‘)
    except Exception as e:  #Exception可以允许你不事先指定错误原因 只要检测到 异常 就会执行 
        print(‘Error:‘, e)
    finally:
        print(‘finally...‘)

#Python内置的logging 模块 
#可以记录下来错误 通过配置，logging还可以把错误记录到日志文件里，方便事后排查
import logging

def foo(s):
    return 10 / int(s)

def bar(s):
    return foo(s) * 2

def main():
    try:
        bar(‘0‘)
    except Exception as e:
        logging.exception(e)

main()
print(‘END‘)

class FooError(ValueError):
    pass
a= 1
if a != 0:
    raise FooError(‘invalid value: %s‘ % s)
else:
    print(‘ok‘)


-----------------------------------
Traceback (most recent call last):
  File "C:/Users/hxsd/PycharmProjects/helloWorld/类的__slots__.py", line 47, in <module>
    raise FooError(‘invalid FooError‘)  #自定义抛出的错误信息
__main__.FooError: invalid FooError