[Numpy-discussion] np.in1d() & sets, bug?

[Nathaniel Smith]

Another case where refusing to implicitly create object arrays would have
avoided a lot of confusion...
On Aug 10, 2015 10:13 AM, "Sebastian Berg" <sebastian at sipsolutions.net>
wrote:

> On Mo, 2015-08-10 at 12:09 -0400, Benjamin Root wrote:
> > Just came across this one today:
> >
> > >>> np.in1d([1], set([0, 1, 2]), assume_unique=True)
> > array([ False], dtype=bool)
> >
> > >>> np.in1d([1], [0, 1, 2], assume_unique=True)
> >
> > array([ True], dtype=bool)
> >
> >
> > I am assuming this has something to do with the fact that order is not
> > guaranteed with set() objects? I was kind of hoping that setting
> > "assume_unique=True" would be sufficient to overcome that problem.
> > Should sets be rejected as an error?
> >
>
> Not really, it is "simply" because ``np.asarray(set([1, 2, 3]))``
> returns an object array and 1 is not the same as ``set([1, 2, 3])``.
>
> I think earlier numpy versions may have had "short cuts" for short lists
> or something so this may have worked in some cases....
>
> - Sebastian
>
>
> >
> > This was using v1.9.0
> >
> >
> > Cheers!
> >
> > Ben Root
> >
> > _______________________________________________
> > NumPy-Discussion mailing list
> > NumPy-Discussion at scipy.org
> > http://mail.scipy.org/mailman/listinfo/numpy-discussion
>
>
> _______________________________________________
> NumPy-Discussion mailing list
> NumPy-Discussion at scipy.org
> http://mail.scipy.org/mailman/listinfo/numpy-discussion
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.python.org/pipermail/numpy-discussion/attachments/20150810/9199ea9a/attachment.html>