title: find same datetime in arrays of different lengths
body: <p>Consider the following arrays of julian dates</p>
  
  <pre><code>Jday1 = datenum('2011-01-01 00:00','yyyy-mm-dd HH:MM'):60/(60*24):...
      datenum('2011-12-31 23:00','yyyy-mm-dd HH:MM');
  Jday2 = datenum('2011-04-01 00:00','yyyy-mm-dd HH:MM'):60/(60*24):...
      datenum('2011-12-31 23:00','yyyy-mm-dd HH:MM');
  Jday3 = datenum('2011-02-06 00:00','yyyy-mm-dd HH:MM'):60/(60*24):...
      datenum('2011-12-31 22:00','yyyy-mm-dd HH:MM');
  </code></pre>
  
  <p>which are all of different length and have different time within them.</p>
  
  <p>How would it be possible to find which dates are the same in the 3 arrays i.e. return the index of the consistent dateTime between all of the arrays?</p>
  
  <p>I know I could use strcmp if they were the same size but what would I do if they are of different lengths as in the example? Also, strcmp would be an issue here due to the number of arrays being 3 not 2.</p>