Step further with filebasedMessages

[Cecil Westerhof]

Op Tuesday 5 May 2015 15:57 CEST schreef Ian Kelly:

> On May 5, 2015 5:46 AM, "Cecil Westerhof" <Cecil at decebal.nl> wrote:
>>
>> Op Tuesday 5 May 2015 12:41 CEST schreef Steven D'Aprano:
>>
>>> # Untested. def get_message_slice(message_filename, start=0,
>>> end=None, step=1): real_file = expanduser(message_filename)
>>> messages = [] # FIXME: I assume this is expensive. Can we avoid
>>> it? nr_of_messages = get_nr_of_messages(real_file)
>>
>> If I want to give the possibility to use negative values also, I
>> need the value.
>
> You could make this call only if one of the boundaries is actually
> negative. Then callers that provide positive values don't need to
> pay the cost of that case.

You have a point there. I will think about it.


> Alternatively, consider that it's common for slices of iterators to
> disallow negative indices altogether, and question whether you
> really need that.

It was an idea I got from this newsgroup. :-D And I liked it,
otherwise I would not have implemented it.

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