[Numpy-discussion] array comprehension

[Nathaniel Smith]

Are you sure fromiter doesn't make an intermediate list or equivalent? It
has to collect all the values before it can know the shape or dtype of the
array to put them in.

On Nov 4, 2016 5:26 AM, "Francesc Alted" <faltet at gmail.com> wrote:



2016-11-04 13:06 GMT+01:00 Neal Becker <ndbecker2 at gmail.com>:

> I find I often write:
> np.array ([some list comprehension])
>
> mainly because list comprehensions are just so sweet.
>
> But I imagine this isn't particularly efficient.
>

Right.  Using a generator and np.fromiter() will avoid the creation of the
intermediate list.  Something like:

np.fromiter((i for i in range(x)))  # use xrange for Python 2


>
> I wonder if numpy has a "better" way, and if not, maybe it would be a nice
> addition?
>
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-- 
Francesc Alted

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