Python error handling: try. Except. Finally/logging/raise

Source: Internet
Author: User
Tags integer division

Python Error inheritance table:

Https://docs.python.org/3/library/exceptions.html#exception-hierarchy


Format:

def function ():

Try

Content # # #正确输出

Except error table in E:

Output Content # # #错误输出

Finally

Output Content # #必定输出

Print (' END ') # #必定输出


#!/usr/bin/python#-*-coding:utf-8-*-def foo (s): Return 10/int (s) def Bar (s): return foo (s) * 2def main (): TR Y:bar (' 0 ') except Exception as E:print (' Error: ', e) finally:print (' finally ... ') Main ( )

Operation Result:

(' Error: ', zerodivisionerror (' integer division or modulo by Zero ',)) finally ...


A. In the face of function layer calls, try...except can be captured.

B. Subclasses of the class can also be captured, such as capturing valueerror errors, and by the way the Unicodeerror are captured.

+--ValueError |         +--Unicodeerror |         +--Unicodedecodeerror |         +--Unicodeencodeerror | +--Unicodetranslateerror



Logging errors to the log file:

#!/usr/bin/python#-*-coding:utf-8-*-import logging ########## #记得导入模块def foo (s): Return 10/int (s) def Bar (s): RE        Turn foo (s) * 2def main (): Try:bar (' 0 ') except Exception as E:logging.exception (e) ######## #模块函数使用 Print (' haha ') main () print (' END ')

Operation Result:

hahaenderror:root:division by zerotraceback  (most recent call last):   File  "/usercode/file.py",  line 14, in main    bar (' 0 ')   File  "/usercode/file.py",  line 10, in bar    return  foo (s)  * 2  File  "/usercode/file.py", line 7, in foo     return 10 / int (s) Zerodivisionerror: division by zero 


When debugging without error, normal program error will call stack Traceback prompt error

def foo (s): Return 10/int (s) def Bar (s): return foo (s) * 2def main (): Bar (' 0 ') main ()

Operation Result:

Traceback (most recent): File "/usercode/file.py", line, <module> Main () file "/usercode/file.p  Y ", line one, in main bar (' 0 ') of file"/usercode/file.py ", line 8, in Bar return foo (s) * 2 File"/usercode/file.py ", Line 5, in Foo return 10/int (s) Zerodivisionerror:integer division or modulo by zero



Throw error: Raise

def foo (s): n = Int (s) if n==0:raise valueerror (' Invalid value:%s '% s) return 10/ndef bar (): Try: Foo (' 0 ') except ValueError as E:print (' valueerror! ', e) Raisebar ()

Operation Result:

(' valueerror! ', ValueError (' Invalid value:0 ',)) Traceback (most recent call last): File "/usercode/file.py", line +, in <module> bar () file "/usercode/file.py ", line A, in Bar foo (' 0 ') File"/usercode/file.py ", line 7, foo raise ValueError (' Invalid value:%s '% s) value Error:invalid value:0



Python error handling: try. Except. Finally/logging/raise

Related Article

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

  • Sales Support

    1 on 1 presale consultation

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.