How to construct matrix from vectors?
Nasser M. Abbasi
nma at 12000.org
Sun Jun 21 01:21:34 EDT 2015
On 6/20/2015 10:47 PM, Nasser M. Abbasi wrote:
> I did manage to find a way:
>
> ---------------------------------
> r1 =np.hstack([(v1,v2)]).T
> r2 =np.hstack([(v3,v4)]).T
> mat = np.vstack((r1,r2))
> -----------------------------
>
> Out[211]:
> array([[ 1, 4],
> [ 2, 5],
> [ 3, 6],
> [ 7, 10],
> [ 8, 11],
> [ 9, 12]])
>
> But it is not as intuitive as with Matlab, where one can just write
>
> -------------------------------
> v1=[1,2,3]'; v2=[4,5,6]';
> v3=[7,8,9]'; v4=[10,11,12]';
> m=[v1 v2;v3 v4]
> -------------------------------
Here is a way a little closer to Matlab's method: First
make all the vectors column vectors
v1=np.array([(1,2,3)]).T
v2=np.array([(4,5,6)]).T
v3=np.array([(7,8,9)]).T
v4=np.array([(10,11,12)]).T
mat =np.hstack(( np.vstack((v1,v3)), np.vstack((v2,v4))) )
Out[236]:
array([[ 1, 4],
[ 2, 5],
[ 3, 6],
[ 7, 10],
[ 8, 11],
[ 9, 12]])
There are way too many '(([[]]))' things in Python :)
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