[Numpy-discussion] RFC: out of range slice indexes

Timothy Hochberg tim.hochberg@ieee....
Mon Jan 14 14:03:51 CST 2008


On Jan 14, 2008 12:37 PM, Neal Becker <ndbecker2@gmail.com> wrote:

> I've never liked that python silently ignores slices with out of range
> indexes.  I believe this is a source of bugs (it has been for me).  It
> goes
> completely counter to the python philosophy.
>
> I vote to ban them from numpy.
> >>> from numpy import array
> >>> x = array (xrange (10))
> >>> x[11]
> Traceback (most recent call last):
>  File "<stdin>", line 1, in <module>
> IndexError: index out of bounds
> >>> x[:12] = 2
> >>> x
> array([2, 2, 2, 2, 2, 2, 2, 2, 2, 2])
> >>> len (x)
> 10
>
> Silently ignoring the error x[:12] is a bad idea, IMO.  If it meant to
> _extend_ x to have lenght 12, at least _that_ would be reasonable (but I'm
> not advocating that position).
>
> I believe that out of bounds indexes should always throw IndexError.  We
> can't change that in Python now, but maybe we can in numpy.
> <http://projects.scipy.org/mailman/listinfo/numpy-discussion>



-1. Regardless of the possible merit of this on it's face, I think this is
an area we should maintain compatibility with Python sequences. Not to
mention that it would likely break a bunch of code, including my own.



-- 
.  __
.   |-\
.
.  tim.hochberg@ieee.org
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