[Numpy-discussion] Suggestion: special-case np.array(range(...)) to be faster

[Chris Barker]

On Sun, Feb 14, 2016 at 11:41 PM, Antony Lee <antony.lee at berkeley.edu>
wrote:

> So how can np.array(range(...)) even work?
>

range()  (in py3) is not a generator, nor is is a iterator. it is a range
object, which is lazily evaluated, and satisfies both the iterator protocol
and the sequence protocol (at least most of it:

In [*1*]: r = range(10)


In [*2*]: r[3]

Out[*2*]: 3


In [*3*]: len(r)

Out[*3*]: 10


In [*4*]: type(r)

Out[*4*]: range

In [*9*]: isinstance(r, collections.abc.Sequence)

Out[*9*]: True

In [*10*]: l = list()

In [*11*]: isinstance(l, collections.abc.Sequence)

Out[*11*]: True

In [*12*]: isinstance(r, collections.abc.Iterable)

Out[*12*]: True
I'm still totally confused as to why we'd need to special-case range when
we have arange().

-CHB



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