delete every nth row or column in a matrix using Python

Question

I am trying to delete every 8th column in a 1024x1024 matrix using this method but it takes a lot of time and it will be more difficult when I have to process millions of matrices. Could you please show me how can I delete every nth row or column starting from a certain row or column and using numpy, scipy or any other Python package?

Many thanks

Saullo G. P. Castro · Accepted Answer · 2015-03-08 10:24:45Z

6

You can use np.delete giving the indices corresponding to every 8th row index. Let a be a 2D array or a matrix:

np.delete(a, list(range(0, a.shape[0], 8)), axis=0)

note the use of axis=0 indicating to operate along the rows. To operate along the columns:

np.delete(a, list(range(0, a.shape[1], 8)), axis=1)

edited Mar 8, 2015 at 10:24

answered Mar 8, 2015 at 10:19

Saullo G. P. Castro

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