Question

How do I extract the first ncolumns from a matrix, or how do i extract the columns from say, column 5 to column 5+n ?

The scenario is that I have a matrix, of dim=(i,j), then I want to look a contiguous blocks of column of length n.
So I want to look at the matrix from column0 to column n, then at column1 to column n+1. etc.
Until I reach the end of my matrix.

Thanks

>>> mat=array(range(0,20)).reshape(2,10)
>>> mat
array([[ 0,  1,  2,  3,  4,  5,  6,  7,  8,  9],
       [10, 11, 12, 13, 14, 15, 16, 17, 18, 19]])

Given n=8.
I want to extract the first 8 columns.

Then the matrix from column [1,11] to column [8,18]

Then the matrix from column [2,12] to column [9,19]

Answer 1

>>> mat[:, 0:8]
array([[ 0,  1,  2,  3,  4,  5,  6,  7],
       [10, 11, 12, 13, 14, 15, 16, 17]])
>>> mat[:, 1:9]
array([[ 1,  2,  3,  4,  5,  6,  7,  8],
       [11, 12, 13, 14, 15, 16, 17, 18]])