title: reading in a file with textscan and ignoring certain lines
body: <p>I have an input file which has rows of integers like this:</p>
  
  <pre><code>1 2 3
  4 5 6
  7 8 9
  </code></pre>
  
  <p>I want to read in the file, I have used the textscan function for this kind of task before.
  But there are a few lines in the data (at random positions) which contain double numbers, for example</p>
  
  <pre><code>&lt;large number of integer lines&gt;
  0.12 12.44 65.34
  &lt;large number of integer lines&gt;
  </code></pre>
  
  <p>When reading in the file, I want to <strong>ignore</strong> these lines. What's the best approach to do this? Can I tell textscan to ignore certain patterns?</p>