[SciPy-user] Adding new columns to 2D array & populating them from another array.
Alan G Isaac
aisaac at american.edu
Fri Jun 6 12:46:36 EDT 2008
On Fri, 06 Jun 2008, Dharhas Pothina apparently wrote:
> I have an array 'a'
> a =
> array([[2006, 1, 3, 9, 40],
> [2006, 1, 3, 10, 9],
> [2006, 1, 3, 10, 40],
> ...,
> [2008, 3, 20, 10, 27],
> [2008, 3, 20, 10, 51],
> [2008, 3, 20, 12, 2]])
> where a.shape = (420, 5)
> I have other arrays b,c etc of the shape (420,) (say b contains all 99's and c contains all 50's)
> how to I add the new arrays to 'a' to form an array
> array([[2006, 1, 3, 9, 40 , 99, 50],
> [2006, 1, 3, 10, 9, 99 , 50],
> [2006, 1, 3, 10, 40, 99, 50],
> ...,
> [2008, 3, 20, 10, 27, 99, 50 ],
> [2008, 3, 20, 10, 51, 99, 50],
> [2008, 3, 20, 12, 2, 99, 50]])
>>> import numpy as np
>>> x = np.ones((10,3))
>>> y = np.ones((10,))*2
>>> z = np.ones((10,))*3
>>> np.hstack([x,y[:,None],z[:,None]])
array([[ 1., 1., 1., 2., 3.],
[ 1., 1., 1., 2., 3.],
[ 1., 1., 1., 2., 3.],
[ 1., 1., 1., 2., 3.],
[ 1., 1., 1., 2., 3.],
[ 1., 1., 1., 2., 3.],
[ 1., 1., 1., 2., 3.],
[ 1., 1., 1., 2., 3.],
[ 1., 1., 1., 2., 3.],
[ 1., 1., 1., 2., 3.]])
>>>
hth,
Alan Isaac
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