I have created a matrix out of another matrix. I now want to find the index values for those specific numbers in the 2nd matrix FROM the 1st matrix. How would I go about doing that?

matrix_1=[11 50;
    12 80;
    13 120;
    14 140;
    15 180;
    16 210;
    17 250;
    18 275;
    19 325;
    20 400;
    19 350;
    18 300;
    17 240;
    16 200;
    15 190;
    14 150;
    13 100;
    12 75;
    10 25]

matrix_2=[11 50;
    20 400;
    10 25]

I want to create another matrix that lists the index numbers for matrix 2. So it would look something like idx=[1; 10; 19]

Answer 1

[Jan]

[ex, index] = ismember(matrix_2, matrix_1, 'rows')

[Catherine Mohs]

Thank you!