[Numpy-discussion] Numeric/numpy difference

Travis Oliphant oliphant.travis at ieee.org
Tue Jan 24 08:01:08 CST 2006


Jens Jorgen Mortensen wrote:

> I just discovered (the hard way) that:
>
> >>> import numpy
> >>> a = numpy.empty((2, 3))
> >>> a[:] = [1, 2]
> >>> a
> array([[1, 2, 1],
>        [2, 1, 2]])
>
> This is with revision 1984.  With Numeric I get "ValueError: matrices 
> are not aligned for copy", which I think is the correct answer.

Well, not necessarily.   This is consistent behavior with a[:] = 3 which 
fills the array with 3's.  What's happening is that the array is being 
filled with [1,2] repeatedly (in C-contiguous order).

-Travis





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