Question

Lets say i have an array in PHP

$test['michael_unique_id'] = 3;
$test['john_unique_id'] = 8;
$test['mary_unique_id'] = 10;
.
.
.
.
$test['jimmy_unique_id'] = 4;

(the values (3,8,10………4) are unique)

Lets say i want to search for the unique id 10, and get the order of the matching element in the array. In this example, the third element has the value 10, so i should get the number 3.

I can do it by scanning with a for loop looking for the value i’m searching and then get the $i value when i have a match, but i wonder if there is any built-in function (or a better method) that implements this.

Answer 1

You can get all of the array’s values as an array with array_values() and then use array_search() to get the position (offset) of that value in the array.

$uniq_id  = 10;
$all_vals = array_values($test);  // => array(3, 8, 10, ... )
echo array_search( $uniq_id, $all_vals ); // => 2

Because PHP array indices are zero-based, you’ll get 0 for the first item, 1 for the second item, etc. If you want the first item to be “1,” then just add one. All together now:

$uniq_id = 10;

echo array_search( $uniq_id, array_values( $test ) ) + 1; // => 3

It’s not clear to me, however, that this is necessarily as performant as just doing a foreach:

$uniq_id  = 10;
$idx      = 1;

foreach($test as $val) {
  if($val == $uniq_id) {
    break;
  }

  $idx++;
}

echo $idx; // => 3