[SciPy-user] inverse of column_stack

Robert Kern robert.kern at gmail.com
Tue Feb 21 11:52:30 CST 2006


Ryan Krauss wrote:
> Is there an inverse function to column_stack?  i.e. I want to iterate
> over the columns of a matrix.  I could first transpose it and then
> call tolist, but I was wondering if there was some clean, fast, built
> in way that I wasn't aware of.

You can iterate over arrays.

In [1]: a = reshape(arange(12),(3,4))

In [2]: a
Out[2]:
array([[ 0,  1,  2,  3],
       [ 4,  5,  6,  7],
       [ 8,  9, 10, 11]])

In [3]: for x in a:
   ...:     print x
   ...:
   ...:
[0 1 2 3]
[4 5 6 7]
[ 8  9 10 11]

In [4]: for x in transpose(a):
   ...:     print x
   ...:
   ...:
[0 4 8]
[1 5 9]
[ 2  6 10]
[ 3  7 11]

-- 
Robert Kern
robert.kern at gmail.com

"In the fields of hell where the grass grows high
 Are the graves of dreams allowed to die."
  -- Richard Harter



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