title: read complicated .txt file into Matlab
body: <p>I would like to read a .txt file into Matlab. 
  One of the columns contains both letters and numbers.
  (So I guess one way is to read this column is as string.)</p>
  
  <p>The problem is I also need to find out numbers which are larger than 5 within that column.</p>
  
  <p>e.g. The .txt looks like</p>
  
  <pre><code>12 1
  21 2
  32 7
  11 a
  03 b
  22 4
  13 5
  31 6
  </code></pre>
  
  <p>i.e. Ultimately, I would like to get </p>
  
  <pre><code>32 7
  31 6
  </code></pre>
  
  <p>How can I get it?? Any experts, please help!</p>