Create multidimensional array unique for any single key index.

array_unique_multidimesional.php

<?php

// https://www.php.net/manual/en/function.array-unique.php#116302

$details = array(
    0 => array("id"=>"1", "name"=>"Mike",    "num"=>"9876543210"),
    1 => array("id"=>"2", "name"=>"Carissa", "num"=>"08548596258"),
    2 => array("id"=>"1", "name"=>"Mathew",  "num"=>"784581254"),
);

$details = array_unique_multidimesional($details,'id');

function array_unique_multidimesional($array, $key) {
    $temp_array = array();
    $i = 0;
    $key_array = array();
   
    foreach($array as $val) {
        if (!in_array($val[$key], $key_array)) {
            $key_array[$i] = $val[$key];
            $temp_array[$i] = $val;
        }
        $i++;
    }
    return $temp_array;
}