MATLAB: How to return the rows with specific value

Question

I have a simple matrix

X =

    0  1  2
    1  1  2
    2  2.5  4.5
    3  2  2
    4  4  1.5
    5  4  2.5

and another matrix

    out = [3;4]

I'd like to return the rows in X whose rows start with any value in out

The output should look like

    3  2  2
    4  4  1.5

I tried this code

    xx= X(X(:,1)==any(out),:)

but this always return the first row.

Any suggestion please Thanks in advance

Answer 1

Y=X(ismember(X(:,1),out),:)