PHP Arrays Sorting an Array Using a Method Instead of a Function

PHP Arrays

Sorting an Array Using a Method Instead of a Function

Problem

You want to define a custom sorting routine to order an array. However, instead of using a function, you want to use an object method.

Solution

Pass in an array holding a class name and method in place of the function name:

             usort($access_times, array('dates', 'compare'));

Discussion

As with a custom sort function, the object method needs to take two input arguments and return 1, 0, or −1, depending on whether the first parameter is larger than, equal to, or less than the second:

             class sort {
                     // reverse-order string comparison
                     static function strrcmp($a, $b) {
                             return strcmp($b, $a);
                     }
             }

             usort($words, array('sort', 'strrcmp'));


It must also be declared as static. Alternatively, you can use an instantiated object:

             class Dates {
                     public function compare($a, $b) { /* compare here */ }
             }

             $dates = new Dates;
             
             usort($access_times, array($dates, 'compare'));