MATLAB: How do you extract even columns and even rows from an nxn matrix

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How do you extract even columns and even rows from an nxn matrix?

I have a matrix of 2574 x 5148 and I only need the even columns and even rows.

Thanks!

YourMatrix(2:2:end, 2:2:end)

use rem to determine which list of numbers is even or odd

X = [1 3 4 2 5 4 2] % hint X is the first column of your matrix
iseven = rem(X,2)==0

use this logical vector to select the whole row of M

Are the submatrices in cell array? For example, try something like this

n = 9;
A = rand(n);
k = 3;
B = mat2cell(A, k*ones(1,n/k), k*ones(1,n/k));
diag_all = cellfun(@diag, B, 'uni', 0);