matrix

I have a matrix where the first column contains values of either 211, 212 or 213 where the rows starting with 211 contains the data and the other rows contain random numerals. How would I take only the rows which contained 211 in the first column and disregard the others. So, basically re-define the matrix to only contain the rows starting with 211?

cheers

Answer 1

[Jan]

M = [211, 3,4,5,6; ...
     212, 5,4,3,2; ...
     213, 7,6,4,3; ...
     211, 1,2,3,4];
index = (M(:, 1) == 211);
M2 = M(index, :);