PHP-Sort array based on another array?

Question

OK, I already got this question in stackoverflow but sadly it's in javascript - Javascript - sort array based on another array

and I want it in PHP

$data = array(
   "item1"=>"1",
   "item2"=>"3",
   "item3"=>"5",
   "item4"=>"2",
   "item5"=>"4"
);

to match the arrangement of this array:

sortingArr = array("5","4","3","2","1");

and the output I'm looking for:

$data = array(
    "item3"=>"5",
    "item5"=>"4",
    "item2"=>"3",
    "item4"=>"2",
    "item1"=>"1"
 );

Any idea how this can be done? Thanks.

Answer 1

For a detailed answer, why array_multisort does not match your needs, view this answer, please: PHP array_multisort not sorting my multidimensional array as expected

In short: You want to sort an array based on a predefined order. The Answer is also given over there, but i copied one solution to this answer, too:

Use usort and array_flip, so you be able to turn your indexing array (ValueByPosition) into a PositionByValue Array.

    $data = array(
   "item1"=>"1",
   "item2"=>"3",
   "item3"=>"5",
   "item4"=>"2",
   "item5"=>"4"
);

usort($data, "sortByPredefinedOrder");

function sortByPredefinedOrder($leftItem, $rightItem){
  $order = array("5","4","3","2","1");

  $flipped = array_flip($order);

  $leftPos = $flipped[$leftItem];
  $rightPos = $flipped[$rightItem];
  return $leftPos >= $rightPos;   
}

print_r($data);
// usort: Array ( [0] => 5 [1] => 4 [2] => 3 [3] => 2 [4] => 1 )
// uasort: Array ( [item3] => 5 [item5] => 4 [item2] => 3 [item4] => 2 [item1] => 1 )

However this would require you to predict all possible items inside the predefined order array, or thread other items in an appropriate way.

If you want to maintain the assoc keys, use uasort instead of usort.

Answer 2

Pretty simple ?

$data = array(
   "item1"=>"1",
   "item2"=>"3",
   "item3"=>"5",
   "item4"=>"2",
   "item5"=>"4"
);

$sortingArr = array("5","4","3","2","1");

$result = array(); // result array
foreach($sortingArr as $val){ // loop
    $result[array_search($val, $data)] = $val; // adding values
}
print_r($result); // print results

Output:

Array
(
    [item3] => 5
    [item5] => 4
    [item2] => 3
    [item4] => 2
    [item1] => 1
)