Simple question about Python lists

[Guilherme Polo]

On Tue, Nov 11, 2008 at 5:47 PM, Eric <eric.shain at gmail.com> wrote:
> I'm learning Python (while coming from MATLAB). One question I have is
> that if I have a list with say 8 elements, and I want just a few of
> them how do I select them out. In MATLAB, if I just want the first,
> fifth and eighth element I might do something like this:
>
> b = a([1 5 8]);
>
> I can't seem to figure out a similar Python construct for selecting
> specific indices. Any suggestions?
>

MATLAB works with 1-based index, while Python is 0-based, so accessing
the index number 8 wouldn't be valid with 8 elements here in Python.

Now, to solve your problem you could either use the already suggested
answer above mine or depending on what you what else you wanna do, you
will feel more comfortable using numpy.

Supposing you have a array with 8 elements: x = numpy.arange(8)
To pull out the first, fifth and eighth elements you would do:
x[numpy.array([0, 4, 7])]

It is so no natural as it was in MATLAB, but well, it was a different language.

> Thanks,
>
> Eric
> --
> http://mail.python.org/mailman/listinfo/python-list
>



-- 
-- Guilherme H. Polo Goncalves