Sorting associative array elements in PHP

Question

i have got an associative array as follows:

$data['england']='pound'
$data['america']='dollar'
$data['europe']='euro'
$data['denmark']='krone'
$data['japan']='yen'

I want to sort this array and after that i want 'europe' to be the first element in the array. To sort the array, i am using ksort() in php, now how can i get hold of the 'europe' array object so that i can make it the first element and shift all the remaining elements down?

Answer 1

One solution would be to first remove europe from the array and then do the ksort. When the array is sorted you can use the array_unshift() or array_merge() to add europe as the first element in the array.

An example using merge:

<?php
$data['england']='pound';
$data['america']='dollar';
$data['europe']='euro';
$data['denmark']='krone';
$data['japan']='yen';

unset($data['europe']);
ksort($data);
$data = array('europe' => 'euro') + $data;

print_r($data);
?>

Usage of the + operator will not reindex the array as the merge-operator would.

Answer 2

You could use a callback for sorting:

$data = array (
  'england' => 'pound',
  'america' => 'dollar',
  'europe' => 'euro',
  'denmark' => 'krone',
  'japan' => 'yen'
);

uksort($data, function($a, $b) {
  if($a == 'europe') return -1;
  if($b == 'europe') return 1;
  return $a > $b;
});