PHP/Data Structure/usort

Sorting an Array Using Comparison Functions

   <source lang="html4strict">

<?php

 function evenfirst($i, $j)
 {
   $value = 0;
   if($i % 2)$value++;
   if($j % 2)$value--;
   if($value == 0)
     $value = $i < $j;
   return $value;
 }
 $clothes = array( "hats" => 75, "coats" => 32, "shoes" => 102,
                   "gloves" => 15, "shirts" => 51, "trousers" => 44);
 usort($clothes, "evenfirst");
 var_export($clothes);

?>

 </source>
   
  

usort() sorts an array based on your own predefined criteria.

   <source lang="html4strict">

Its syntax is: void usort(array array, string function_name) <?

   $vocab = array("S123","A1234", "P12345", "A1234567","T");
   
   function compare_length($str1, $str2) {
        $length1 = strlen($str1);
        $length2 = strlen($str2);
   
        if ($length1 == $length2) :
             return 0;
        elseif ($length1 < $length2) :
             return -1;
        else :
             return 1;
        endif;
   }
   usort($vocab, "compare_length");
   
   while (list ($key, $val) = each ($vocab)) {
        echo "$val
";
   }

?>

 </source>