Slicing matrix

[Anthony Liu]

Hi, Robert, 

Thanks a lot.

I figure it out, too.  NumArray is so flexible, it's
like cutting the cheese.  You can cut it anyway you
want.  I really like NumArray.



--- Robert Kern <robert.kern at gmail.com> wrote:

> Anthony Liu wrote:
> > I am using numarray.
> 
> I will be using numpy for this post, and if you are
> new to numarray, then you
> should probably skip it and use numpy instead. All
> new development is going
> towards numpy.
> 
>   http://numeric.scipy.org/
> 
> > Suppose I have
> > 
> >>>>p = array(range(25), shape=(5,5))
> >>>>p
> > 
> > array([[ 0,  1,  2,  3,  4],
> >        [ 5,  6,  7,  8,  9],
> >        [10, 11, 12, 13, 14],
> >        [15, 16, 17, 18, 19],
> >        [20, 21, 22, 23, 24]])
> 
> In [4]: from numpy import *
> 
> In [5]: p = arange(25).reshape((5,5))
> 
> In [6]: p
> Out[6]:
> array([[ 0,  1,  2,  3,  4],
>        [ 5,  6,  7,  8,  9],
>        [10, 11, 12, 13, 14],
>        [15, 16, 17, 18, 19],
>        [20, 21, 22, 23, 24]])
> 
> > How do I easily slice out [0,1,2]
> 
> In [7]: p[0, :3]
> Out[7]: array([0, 1, 2])
> 
> > or [1,2,3]
> 
> In [9]: p[0, 1:4]
> Out[9]: array([1, 2, 3])
> 
> > or [2,7,12]
> 
> In [10]: p[:3, 2]
> Out[10]: array([ 2,  7, 12])
> 
> > or [7,12,17] and put it in a list?
> 
> In [11]: p[1:4, 2]
> Out[11]: array([ 7, 12, 17])
> 
> -- 
> Robert Kern
> robert.kern at gmail.com
> 
> "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
> 
> -- 
> http://mail.python.org/mailman/listinfo/python-list
> 


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