Question

This is the array

Array
(
    [0] => Array
        (
            [artist] => John Keys
            [postID] => 254
        )

    [1] => Array
        (
            [artist] => Jay Bloom
            [postID] => 249
        )

    [2] => Array
        (
            [artist] => John Keys
            [postID] => 216
        )

    [3] => Array
        (
            [artist] => Angie Belle
            [postID] => 225
        )
)

and I want to remove all duplicates from the artist elements only. Notice that 0 and 2 have the same artist but a different postID. I just want to keep the first occurence of the artist and remove all others. So the result I want to have is

Array
(
    [0] => Array
        (
            [artist] => John Keys
            [postID] => 254
        )

    [1] => Array
        (
            [artist] => Jay Bloom
            [postID] => 249
        )
    [2] => Array
        (
            [artist] => Angie Belle
            [postID] => 225
        )
)

I’ve tried array_unique and also serializing and doing an array_map, nothing seems to work right.

Answer 1

<?php
$array = Array
(
    '0' => Array
        (
            'artist' => 'John Keys',
            'postID' => 254
        ),

    '1' => Array
        (
            'artist' => 'Jay Bloom',
            'postID' => 249
        ),

    '2' => Array
        (
            'artist' => 'John Keys',
            'postID' => 216
        ),

    '3' => Array
        (
            'artist' => 'Angie Belle',
            'postID' => 225
        )
);
$newarray = array();
foreach($array as $key => $val){
  if(!array_key_exists('artist', $newarray)){
    $newarray[$val['artist']] = $val;
  }
}
echo '<pre>';
print_r($newarray);

Edit: using numeric keys:

$newarray = array();
$temp = array();

foreach($array as $key => $val){

   if(!in_array($val['artist'], $temp)){
    $temp[] = $val['artist'];
   }
   if( !array_key_exists(array_search($val['artist'], $temp), $newarray) ){
    $newarray[array_search($val['artist'], $temp)] = $val;
   }

}