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Re: Let exception fire or return None

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Cecil Westerhof wrote:

>> (2) you may want to take measures to limit memory usage, e. g.
>>
>> assert index >= 0
> 
> I put that in, but as first statement.

For the record, this was not a recommended check, but rather a way to 
communicate to the reader of my code that unlike yours it doesn't support 
negative indices.
 
>> try:
>>     [line] = itertools.islice(f, index, index+1)
>> except ValueError:
>>     raise IndexError
>> return line.rstrip()
> 
> In my case it is not important. (The biggest file I use has between
> 100 and 200 lines), but I publish it, so I should do my best to make
> it so lean as possible.

If you keep your 

return f.readlines()[index]

anyway you might allow for negative indices, and then

get_indexed_message(message_filename, -1)

fetches the last message in the file and

get_indexed_message(message_filename, slice(None, None))

fetches a list with all messages.

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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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