[SciPy-user] Concatenating 1D arrays

Robert Kern robert.kern at gmail.com
Thu Feb 9 10:06:54 CST 2006

Rudolph van der Merwe wrote:
> On 2/8/06, Robert Kern <robert.kern at gmail.com> wrote:
>>x = []
>>y = []
>>while have_more_vectors():
>>    x.append(get_column_vector_from_somewhere())
>>    y.append(get_row_vector_from_somewhere())
>>x = hstack(x)
>>y = vstack(y)
> The problem (as far as I know) is that all vectors (1-D arrays) are
> treated as row vectors in Numpy. So the example for y will work, but
> I'm not sure it will work for x. How do you construct a 1-D column
> vector which can then be appended to a list and finally hstacked?

Okay, I presumed get_column_vector_from_somewhere() actually gave you a column
vector. If it's actually giving you shape-(n,) arrays instead of shape-(n,1), use

  x = column_stack(x)


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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