[SciPy-user] Concatenating 1D arrays

Ryan Krauss ryanlists at gmail.com
Wed Feb 8 09:05:08 CST 2006


Growing arrays will be less efficient in NumPy as well (I can't think
of a way to avoid this in any language), because you need to allocate
more memory each time you add a row or column.  I don't know if this
is slightly better in Python vs. Matlab because Python uses references
so much and Matlab makes copies of almost everything.

Ryan

On 2/8/06, Rudolph van der Merwe <rudolphv at gmail.com> wrote:
> > The way I prefer is to initialize x and y with full dimension and "fill"
> > it. This is imho easier to read and shorter.
>
> The problem is that the full dimension, i.e. number of vectors to be
> concatenated is not known apriori. I know that growing arrays in-place
> as apposed to filling a pre-sized array is very inefficient in Matlab
> (is this also the case for Numpy?), but sometimes it cannot be
> avoided.
>
> R.
>
> --
> Rudolph van der Merwe
>
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