[Numpy-discussion] force column vector

Christopher Barker Chris.Barker@noaa....
Wed Feb 7 10:32:36 CST 2007


Christian wrote:
> when creating an ndarray from a list, how can I force the result to be
> 2d *and* a column vector? So in case I pass a nested list, there will be no
> modification of the shape and when I pass a simple list, it will be 
> converted to a 2d column vector.

I'm not sure I understand the specification of the problem. I would 
think that the definition of a column vector is that it's shape is:

(-1,1)

which makes it easy:

def MakeColumn(input):
     a = asarray(input)
     a.shape = (-1,1)
     return a

however, if you want: MakeColumn([[1,2],[3,4],[5,6]])

to return:
array([[1, 2],
        [3, 4],
        [5, 6]])

that's not what I would call a column vector, and if that's what you 
want, then what would you want:

MakeColumn([[1,2,3,4],[5,6,7,8]])

to return?

-Chris



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Christopher Barker, Ph.D.
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