[Numpy-discussion] Inplace index suprise
Robert Kern
robert.kern at gmail.com
Thu Mar 20 15:05:46 EDT 2008
On Thu, Mar 20, 2008 at 1:35 PM, Gael Varoquaux
<gael.varoquaux at normalesup.org> wrote:
> On Thu, Mar 20, 2008 at 06:17:44PM +0000, James Philbin wrote:
> > Hi,
>
> > > This cannot work, because the inplace operation does not
> > > take place as a for loop.
> > Well, this would be fine if I was assigning the values to tempories as
> > you suggest. However, the operation should be performed inplace and
> > this is what I don't understand - why is there no for loop? I think
> > the semantics of these inplace indexed operations is intuitively quite
> > clear and numpy doesn't follow this intuition. Would there be any
> > interest in changing this behaviour in numpy?
>
> I think this is technicaly impossible from the way numpy works. This
> breaks the numpy model that every operation is global on the array.
More importantly, it is technically impossible because of the way that
*Python* works. See the thread "Histograms via indirect index arrays"
for a detailed explanation.
http://projects.scipy.org/pipermail/numpy-discussion/2006-March/006877.html
--
Robert Kern
"I have come to believe that the whole world is an enigma, a harmless
enigma that is made terrible by our own mad attempt to interpret it as
though it had an underlying truth."
-- Umberto Eco
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