subset a matrix on columns in matlab

To subset a matrix on columns in MATLAB, you can use the colon operator. Here is an example:

main.m
% Create a sample matrix
A = [1 2 3; 4 5 6; 7 8 9];

% Subset the matrix on columns 1 and 3
B = A(:, [1, 3]);
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In this example, we have created a matrix A with three columns. To subset the matrix on columns 1 and 3, we use the : operator to select all rows and specify the column indices we want to keep inside brackets.

The resulting matrix B will have the same number of rows as A, but only columns 1 and 3 will be included.

Note that you can also use the colon operator by itself to select all columns of a matrix. For example:

main.m
% Select all columns of the matrix
B = A(:, :);
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In this case, B will be equal to A, since we selected all columns.