PHP custom ordering array - php

Question

An array arrives with some or all of the following values, in any order. What's the best way to order them in ascending size order? So starting with small and ending with XXL. I can usort but am a bit lost as to how the elements should be ordered in my user defined function
Small
XXL
Medium
Large
XL
EDIT: left out some info so created new question Custom ordering array with key / value pairs
EDIT2: Full code
print_r($sizes);
$sorted_sizes = $this->sort_sizes(array_unique($sizes));
print_r($sorted_sizes);
function sort_sizes($sizes)
{
return uasort($sizes, array($this, 'cmp'));
}
function cmp($a,$b)
{
$sizeArray = array( 'Small' => 0, 'Medium' => 1, 'Large' => 2, 'XL' => 3, 'XXL' => 4);
return $sizeArray[$a] - $sizeArray[$b];
}
This outputs:
Array
(
[66-507cddcd16d9786abafccfa78b19acf8] => XL
[64-507cddcd16d9786abafccfa78b19acf8] => medium
[65-507cddcd16d9786abafccfa78b19acf8] => large
[63-507cddcd16d9786abafccfa78b19acf8] => small
)
and print_r($sorted_sizes) just gives output "1"

Answer 1

Updated answer according to full code
The first issue here is that you're returning the result of uasort():
function sort_sizes($sizes)
{
return uasort($sizes, array($this, 'cmp'));
}
That's wrong, because uasort() does not return the sorted array. It modifies the same variable that you pass as a parameter, and returns a boolean value. That's why you see 1 as output.
Make the method accept $sizes by reference:
function sort_sizes(array &$sizes)
{
uasort($sizes, array($this, 'cmp'));
}
Then call it like so:
print_r($sizes);
$sorted_sizes = array_unique($sizes);
$this->sort_sizes($sorted_sizes);
print_r($sorted_sizes);
Here's your cmp() method, with added support for case-insensitive sorting:
function cmp($a, $b)
{
$sizes = array('small' => 0, 'medium' => 1, 'large' => 2, 'xl' => 3, 'xxl' => 4);
return $sizes[strtolower($a)] - $sizes[strtolower($b)];
}
Old answer
Try this. Use uasort() instead if you want to maintain key-value pairs:
function sort_sizes($a, $b) {
// Map the sizes to an ordered sequence of ints
static $sizes = array('small' => 0, 'medium' => 1, 'large' => 2, 'xl' => 3, 'xxl' => 4);
// Find the difference, using the sizes as keys to the above array
return $sizes[strtolower($a)] - $sizes[strtolower($b)];
}
$arr = array('Small', 'XXL', 'Medium', 'Large', 'XL');
print_r($arr); // Before sorting
uasort($arr, 'sort_sizes');
print_r($arr); // After sorting
Output:
Array
(
[0] => Small
[1] => XXL
[2] => Medium
[3] => Large
[4] => XL
)
Array
(
[0] => Small
[2] => Medium
[3] => Large
[4] => XL
[1] => XXL
)

Answer 2

You can do this using array_multisort:
$orderIndex = array_flip(array('Small','Medium','Large','XL','XXL'));
$arr = array('Small','XXL','Medium','Large','XL');
array_multisort(array_map(function($val) use ($orderIndex) { return $orderIndex[$val]; }, $arr), $arr);
Here array_map is used with an anonymous function to build an array of the “weight” of each value in $arr. That array is then used to order the values in $arr.
This is basically the same as BoltClock suggested just with doing the comparison on the already calculated “weights”.

Answer 3

Do the sorting in two phases. First, convert text to a convenient numeric value. In this moment you should decide if "L" and "Large" map to the same value or not. Then reorder the array based on those numeric conversions.