[Numpy-discussion] Multi-dimensional array of splitted array

[Sebastian Berg]

On Mi, 2016-03-23 at 10:02 -0400, Joseph Fox-Rabinovitz wrote:
> On Wed, Mar 23, 2016 at 9:37 AM, Ibrahim EL MEREHBI
> <bobmerhebi at gmail.com> wrote:
> > Thanks Eric. I already checked that. It's not what I want. I think
> > I wasn't
> > clear about what I wanted.
> > 
> > I want to split each column but I want to do it for each column and
> > end up
> > with an array. Here's the result I wish to have:
> > 
> > array([[[0], [1, 2, 3, 4], [5, 6, 7], [8, 9]],
> >        [[10], [11, 12, 13, 14], [15, 16, 17], [18, 19]],
> >        [[20], [21, 21, 23, 24], [25, 26, 27], [28, 29]]],
> > dtype=object)
> > 
> 
> Apply [`np.stack`](http://docs.scipy.org/doc/numpy-1.10.0/reference/g
> enerated/numpy.stack.html#numpy.stack)
> to the result. It will merge the arrays the way you want.
> 


It is simply impossible to stack those arrays like he wants, it is not
a valid array.

- Sebastian


>     -Joe
> 
> > 
> > Sincerely Yours,
> > Bob
> > 
> > 
> > 
> > On 23/03/2016 14:17, Eric Moore wrote:
> > 
> > Try just calling np.array_split on the full 2D array.  It splits
> > along a
> > particular axis, which is selected using the axis argument of
> > np.array_split.  The axis to split along defaults to the first so
> > the two
> > calls to np.array_split below are exactly equivalent.
> > 
> > In [16]: a = np.c_[:10,10:20,20:30]
> > 
> > 
> > In [17]: np.array_split(a, [2,5,8])
> > 
> > Out[17]:
> > 
> > [array([[ 0, 10, 20],
> > 
> > [ 1, 11, 21]]), array([[ 2, 12, 22],
> > 
> > [ 3, 13, 23],
> > 
> > [ 4, 14, 24]]), array([[ 5, 15, 25],
> > 
> > [ 6, 16, 26],
> > 
> > [ 7, 17, 27]]), array([[ 8, 18, 28],
> > 
> > [ 9, 19, 29]])]
> > 
> > 
> > In [18]: np.array_split(a, [2,5,8], 0)
> > 
> > Out[18]:
> > 
> > [array([[ 0, 10, 20],
> > 
> > [ 1, 11, 21]]), array([[ 2, 12, 22],
> > 
> > [ 3, 13, 23],
> > 
> > [ 4, 14, 24]]), array([[ 5, 15, 25],
> > 
> > [ 6, 16, 26],
> > 
> > [ 7, 17, 27]]), array([[ 8, 18, 28],
> > 
> > [ 9, 19, 29]])]
> > 
> > 
> > Eric
> > 
> > 
> > 
> > On Wed, Mar 23, 2016 at 9:06 AM, Ibrahim EL MEREHBI <
> > bobmerhebi at gmail.com>
> > wrote:
> > > 
> > > Hello,
> > > 
> > > I have a multi-diensional array that I would like to split its
> > > columns.
> > > 
> > > For example consider,
> > > 
> > > dat = np.array([np.arange(10),np.arange(10,20),
> > > np.arange(20,30)]).T
> > > 
> > > array([[ 0, 10, 20],
> > >        [ 1, 11, 21],
> > >        [ 2, 12, 22],
> > >        [ 3, 13, 23],
> > >        [ 4, 14, 24],
> > >        [ 5, 15, 25],
> > >        [ 6, 16, 26],
> > >        [ 7, 17, 27],
> > >        [ 8, 18, 28],
> > >        [ 9, 19, 29]])
> > > 
> > > 
> > > I already can split one column at a time:
> > > 
> > > np.array_split(dat[:,0], [2,5,8])
> > > 
> > > [array([0, 1]), array([2, 3, 4]), array([5, 6, 7]), array([8,
> > > 9])]
> > > 
> > > 
> > > How can I extend this for all columns and (overwrite or) have a
> > > new
> > > multi-dimensional array?
> > > 
> > > Thank you,
> > > Bob
> > > 
> > > 
> > > _______________________________________________
> > > NumPy-Discussion mailing list
> > > NumPy-Discussion at scipy.org
> > > https://mail.scipy.org/mailman/listinfo/numpy-discussion
> > > 
> > 
> > 
> > 
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> > 
> > 
> > 
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