Re: Let exception fire or return None

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From	Cecil Westerhof <Cecil@decebal.nl>
Newsgroups	comp.lang.python
Subject	Re: Let exception fire or return None
Organization	Decebal Computing
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Date	Thu, 30 Apr 2015 11:13:05 +0200
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Op Thursday 30 Apr 2015 10:18 CEST schreef Dave Angel:

> On 04/30/2015 03:43 AM, Cecil Westerhof wrote:
>> I have a function to fetch a message from a file:
>> def get_indexed_message(message_filename, index):
>> """
>> Get index message from a file, where 0 gets the first message
>> """
>>
>> return open(expanduser(message_filename),
>> 'r').readlines()[index].rstrip()
>>
>> What is more the Python way: let the exception fire like this code
>> when index is to big, or catching it and returning None?
>>
>> I suppose working zero based is OK.
>>
>
> Fire an exception.
>
> One advantage is that the exception will pinpoint exactly which line
> of the function had a problem.

That is what I did. The only ‘problem’ is that they need to catch the
error if they do not know the number of messages in the file. But they
can use get_nr_of_messages for that.

-- 
Cecil Westerhof
Senior Software Engineer
LinkedIn: http://www.linkedin.com/in/cecilwesterhof

Thread

Let exception fire or return None Cecil Westerhof <Cecil@decebal.nl> - 2015-04-30 09:43 +0200
  Re: Let exception fire or return None Dave Angel <davea@davea.name> - 2015-04-30 04:18 -0400
    Re: Let exception fire or return None Cecil Westerhof <Cecil@decebal.nl> - 2015-04-30 11:13 +0200
  Re: Let exception fire or return None Peter Otten <__peter__@web.de> - 2015-04-30 11:30 +0200
    Re: Let exception fire or return None Cecil Westerhof <Cecil@decebal.nl> - 2015-04-30 13:26 +0200
      Re: Let exception fire or return None Peter Otten <__peter__@web.de> - 2015-04-30 14:28 +0200
        Re: Let exception fire or return None Cecil Westerhof <Cecil@decebal.nl> - 2015-04-30 16:53 +0200
      Re: Let exception fire or return None Cecil Westerhof <Cecil@decebal.nl> - 2015-04-30 14:22 +0200
  Re: Let exception fire or return None Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-04-30 14:05 +0200
  Re: Let exception fire or return None Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2015-04-30 14:30 +0200

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