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Sort arrays by key revisited

July 29, 2009 | PHP Scripting

I don’t know why but I have an infatuation with little utility functions. Its pretty stupid, but it keeps me entertained and provides me with a cheap blog post ๐Ÿ˜‰ That and I’ve noticed it trending A LOT in my search keywords lately, so I figure I should post some updated and easier to use code.

A few years ago I posted on Sorting Multidimensional Arrays by Key. The solution had php4 and php5 version and they were class based. Kind of awkward to use. They were originally dumped in a framework and accessed statically. After much tweaking and moving it from project to project it is down to a single function that also sorts arrays of objects my member variables.

<?php

/**
* Sort an array by a key within the array_items
* Items can be arrays or objects, but must all be the same type
*
* @example
* $array = array(
* 'mary' => array('age' => 21),
* 'bob' => array('age' => 5),
* 'justin' => array('age' => 15)
* );
* $array = cf_sort_by_key($array,'age');
* # array is now: bob,justin,mary
*
* @param $data - the array of items to work on
* @param $sort_key - an array key or object member to use as the sort key
* @param $ascending - wether to sort in reverse/descending order
* @return array - sorted array
*/
function array_sort_by_key($data,$sort_key,$ascending=true) {
$order = $ascending ? '$a,$b' : '$b,$a';
ย 
if(is_object(current($data))) {
$callback = create_function($order,'return strnatcasecmp($a->'.$sort_key.',$b->'.$sort_key.');');
} else {
$callback = create_function($order,'return strnatcasecmp($a["'.$sort_key.'"],$b["'.$sort_key.'"]);');
}
ย 
uasort($data,$callback);
return $data;
}

Less code. Easier to use. Single code base for php4 and php5. And once php 5.3 becomes more ubiquitous I can rewrite it again to use lambda functions ๐Ÿ˜‰