MATLAB: Extracting every n number of column from matrix matlab

for loopmatrixmatrix manipulation

0 down vote favorite I need to extract every n number of column from my matrix. Please note that not every nth column. For example I have a matrix:
A =
     1    23    34    53    67    45    67    45
    12    34    45    56    67    87    98    12
     1     2     3    45    56    76    87    56
And I want to extract each 3 column, so my data should be like:
X =
     1    23    34    67    45    67
    12    34    45    67    87    98
     1     2     3    56    76    87
So I would skip 4th column then 8th column and so on. I know how to extract every nth column and row but I couldn't figure it out what I need. Appreciated for your help

Best Answer

Here is a general solution to your problem in which you can specify how many columns to keep and how many to delete
colToKeep = 2;
colToDelete = 3;
ColIndex = mod( 0:size(A,2)-1, colToKeep+colToDelete ) < colToKeep;
A(:, ~ColIndex) = [];
Use colToKeep and colToDelete to specify the values.
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