title: Matlab - Retrieve values from a column(col1) that does not exist in another column (col2)
body: <p>How can I retrieve values ​​from a column(col1) that does not exist in another column (col2)?</p>
  
  <pre><code>col1 = {'C1'; 'D1'; 'H1'; 'L1'; 'M1'}
  
  col2 = {'A1'; 'B1' ; 'C1'; 'D1'; 'E1'}
  </code></pre>
  
  <p>I can not obtain this result:</p>
  
  <pre><code>'H1'
  'L1'
  'M1'
  </code></pre>