algorithm for extracting high and low values from range of db recs
<p>I have a data structure like this:</p>

<pre><code> array (size=10)
   1 =&gt; 
    array (size=2)
     'fdate' =&gt; string '11/05/12' (length=8)
     'ftime' =&gt; string '11:13' (length=5)
   2 =&gt; 
    array (size=2)
    'fdate' =&gt; string '11/05/12' (length=8)
    'ftime' =&gt; string '11:13' (length=5)
   3 =&gt; 
    array (size=2)
     'fdate' =&gt; string '11/05/12' (length=8)
     'ftime' =&gt; string '11:50' (length=5)
  4 =&gt; 
    array (size=2)
     'fdate' =&gt; string '11/05/12' (length=8)
     'ftime' =&gt; string '11:51' (length=5)
  5 =&gt; 
    array (size=2)
     'fdate' =&gt; string '11/07/12' (length=8)
     'ftime' =&gt; string '09:11' (length=5)
  6 =&gt; 
    array (size=2)
     'fdate' =&gt; string '11/07/12' (length=8)
     'ftime' =&gt; string '09:12' (length=5)
  7 =&gt; 
    array (size=2)
     'fdate' =&gt; string '11/07/12' (length=8)
     'ftime' =&gt; string '10:29' (length=5)
  8 =&gt; 
    array (size=2)
     'fdate' =&gt; string '11/08/12' (length=8)
     'ftime' =&gt; string '11:06' (length=5)
  9 =&gt; 
    array (size=2)
    'fdate' =&gt; string '11/08/12' (length=8)
    'ftime' =&gt; string '11:06' (length=5)
  10 =&gt; 
    array (size=2)
    'fdate' =&gt; string '11/08/12' (length=8)
    'ftime' =&gt; string '11:07' (length=5)
</code></pre>

<p>I need to evaluate and end up with the first and last ftime values for each date, in this case </p>

<pre><code> fdate     ftime1 ftime2
 11/05/12, 11:13, 11:51
 11/07/12, 09:11, 10:29
 11/08/12, 11:06, 11:07
</code></pre>

<p>I have a loop like this:</p>

<pre><code> $struct = array();
 $i = 1;
 foreach($recs as $row){            
   $struct[$i]['fdate'] = $row-&gt;fdate;// store fdate
   $struct[$i]['ftime1'] = $row-&gt;ftime;// store initial ftime
   $currentfdate = $row-&gt;fdate; // use $currentfdate in comparison to $row-&gt;fdate

   if($currentfdate &lt;&gt; $row-&gt;fdate){
      $struct[$i]['ftime2'] = $row-&gt;ftime;// store last ftime
   }

   $i++;
 }
</code></pre>

<p>I am not sure how to determine when the fdate changes to trigger the storing of ftime2.</p>
