MATLAB: Remove random columns from a big matrix

columns

Hello,
I have this issue: I want to randomly remove 3000 columns from a big matrix with size 1600X8500. below I have a code I wrote but when I run it the matlab outputs the following error: Index exceeds the number of array elements (1650)
A=[x1 x2 ...] % 1600by8500 matrix
    k=randperm(size(A,1));
    B=A;
    B(:,k(1:3000))=[];
Your help is important!!

Best Answer

If A is 1600 x 8500 as you describe, then the line below will only create 1600 elements so you can't use an index of 1:3000. 
k=randperm(size(A,1));
Instead, you want to use the 2nd dimension of A
k=randperm(size(A,2));
   %              ^
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