[Numpy-discussion] Removing rows and columns of a matrix

Konrad Hinsen hinsen at cnrs-orleans.fr
Mon Jul 28 07:42:11 CDT 2003


On Monday 28 July 2003 16:26, Nils Wagner wrote:
> Konrad Hinsen schrieb:
> > >  How can I delete a column/row from a matrix.
> >
> > As an in-place operation, not at all. To get a copy of an array with some
> > columns/rows removed, use Numeric.take.
>
> The in-place operation of matlab is a nice feature. Is it thinkable to
> have this
> in scipy or numarray at a later date ?

I'd say that the obvious way to implement it is as

  del a[2:3,:]

That can certainly be done, but someone has to do it.

Personally, I am not convinced that it is very useful. The consequences of an 
in-place change can be disastrous when many references point to that array. 
But then, we have other in-place operations which sometimes are handy, so my 
usefulness estimation may be wrong.

Konrad.
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