title: matlab - find indices of elements in x
body: <p>I have a matrix <code>x</code> of size Nx2 (contains (x,y) coordinates) and a matrix <code>c</code> of size Px1 (P&lt;=N) that contains certain x-coordinates which I'm interested in. For example:</p>
  
  <pre><code>x = [10 3; 21 9; 98 54; 4 30; 37 12];
  c = [4 98];
  </code></pre>
  
  <p>I want to get the coordinates of the elements in <code>c</code> (in the above case <code>[4 3]</code>). How can I do this? I've only found a way when <code>c</code> is a 1x1 matrix (i.e. a scalar).</p>