Sorting array

Robert Kern robert.kern at gmail.com
Fri Nov 30 15:55:08 EST 2007


Tartifola wrote:
> 
> Hi,
> I'm working with numerical array and I'm a little lost on a particular
> sorting of one of them. In particular I have an array like
> 
> a = array([[8,4,1],[2,0,9]])
> 
> and I need to sort it using only the first column as reference but
> keeping the lines together so to obtain
> 
> array([[2, 0, 9],
>        [8, 4, 1]])

In [1]: from numpy import *

In [2]: a = array([[8,4,1],[2,0,9]])

In [3]: i = argsort(a[:,0])

In [4]: a[i]
Out[4]:
array([[2, 0, 9],
       [8, 4, 1]])


numpy questions are best asked on the numpy-discussion mailing list since
everyone there automatically knows that you are talking about numpy arrays and
not just misnaming lists.  ;-)

  http://www.scipy.org/Mailing_Lists

-- 
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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