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POPHP: sort array by half-hour intervals
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  1. POPHP: sort array by half-hour intervals
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    copied!<p>I have a very specific problem here. I have a multi-dimensional array that I want to sort first by half-hour time intervals, second by dates. The function <a href="http://us2.php.net/manual/en/function.array-multisort.php" rel="nofollow noreferrer">array_multisort</a> will not meet my requirements.</p> <p>Example: I want:</p> <pre><code>array(array("time"=&gt;"12:15", "date"=&gt;"2009-03-24"), array("time"=&gt;"12:10", "date"=&gt;"2009-03-23"), array("time"=&gt;"12:00", "date"=&gt;"2009-03-24"), array("time"=&gt;"11:30", "date"=&gt;"2009-03-24")); </code></pre> <p>To end up as:</p> <pre><code>array(array("time"=&gt;"11:30", "date"=&gt;"2009-03-24"), array("time"=&gt;"12:10", "date"=&gt;"2009-03-23"), array("time"=&gt;"12:00", "date"=&gt;"2009-03-24"), array("time"=&gt;"12:15", "date"=&gt;"2009-03-24")); </code></pre> <p>I've tried to accomplish this with <a href="http://php.net/manual/en/function.uksort.php" rel="nofollow noreferrer">uksort</a> in combination with my own sorting callback function. This is the code I am currently using:</p> <pre><code>uksort($myArray, "sortThirties"); function sortThirties($a, $b) { //Get the two times as timestamps relative to today $one = strtotime($a['time']); $two = strtotime($b['time']); //Round them down to the nearest half-hour time $one = $one - ($one % 1800); $two = $two - ($two % 1800); //Return the difference if times are unequal //If times are equal, return the difference between dates. return ($one == $two ? strcmp($a['date'],$b['date']) : $one - $two); } </code></pre> <p>Immediately after running this function, I print out the array with print_r(), and the order of the data appears to be random. What am I missing?</p> <p><strong>EDIT</strong>: It turns out, the order <strong>is</strong> <em>completely</em> random. I added this line to the sortThirties function:</p> <pre><code>echo "&lt;BR&gt;",$a['time']," ",$b['time']; </code></pre> <p>and all I got was 50 pages of <code>&lt;BR&gt;</code>'s.</p> <p>I know the array is correctly structured because this code executed on the very same array gives me the unsorted data:</p> <pre><code>foreach($myArray AS $a) { echo "&lt;BR&gt;",$a['date']," ",$a['time']; } </code></pre> <p>The only thing I can think of is there must be a problem with uksort. Any thoughts?</p>
 

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