[Numpy-discussion] array indexing problem

Rahul Kanwar rahul.kanwar at gmail.com
Tue Aug 29 19:05:04 CDT 2006


Hello,

   I am trying to extract a column from a 2D array here is what is have
done:

--------------------------------------------
In [3]: a = array([[1,2,3],[1,2,3]])

In [4]: a
Out[4]:
array([[1, 2, 3],
       [1, 2, 3]])

In [5]: a[:, 1]
Out[5]: array([2, 2])

In [6]: a[:, 1:2]
Out[6]:
array([[2],
       [2]])
--------------------------------------------

when i use a[:, 1] i get a 1x2 array where as when i use a[:, 1:2] i get
a 2x1 array. The intuitive behavior of a[:, 1] should be a 2x1 array. Am
i doing something wrong here or is there some reason for this behavior ?

regards,
Rahul




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