Multi-dimensional array of splitted array
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
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@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) Sincerely Yours, Bob On 23/03/2016 14:17, Eric Moore wrote:
On Wed, Mar 23, 2016 at 9:37 AM, Ibrahim EL MEREHBI <bobmerhebi@gmail.com> wrote:
Apply [`np.stack`](http://docs.scipy.org/doc/numpy-1.10.0/reference/generated/numpy.stack.html#...) to the result. It will merge the arrays the way you want. -Joe
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@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) Sincerely Yours, Bob On 23/03/2016 14:17, Eric Moore wrote:
On Wed, Mar 23, 2016 at 9:37 AM, Ibrahim EL MEREHBI <bobmerhebi@gmail.com> wrote:
Apply [`np.stack`](http://docs.scipy.org/doc/numpy-1.10.0/reference/generated/numpy.stack.html#...) to the result. It will merge the arrays the way you want. -Joe
participants (4)
-
Eric Moore -
Ibrahim EL MEREHBI -
Joseph Fox-Rabinovitz -
Sebastian Berg