php - Comparing two object arrays with array_udiff -

array 1: $tags_result

    array (size=4)   0 =>      object(stdclass)[8]       public 'id_tag' => string '2' (length=1)       public 'tag' => string 'tag 1' (length=5)   1 =>      object(stdclass)[9]       public 'id_tag' => string '5' (length=1)       public 'tag' => string 'tag 4' (length=5)   2 =>      object(stdclass)[10]       public 'id_tag' => string '6' (length=1)       public 'tag' => string 'tag 7' (length=5)   3 =>      object(stdclass)[11]       public 'id_tag' => string '7' (length=1)       public 'tag' => string 'tag 9' (length=5) 

array 2: $post_tags_result

    array (size=2)   0 =>      object(stdclass)[5]       public 'id_tag' => string '2' (length=1)       public 'tag' => string 'tag 1' (length=5)   1 =>      object(stdclass)[6]       public 'id_tag' => string '6' (length=1)       public 'tag' => string 'tag 7' (length=5) 

i'm trying extract values of array 1 not appear in array 2:

function foo($tags_result, $post_tags_result){     return $tags_result->id_tag != $post_tags_result->id_tag; }  $difference_tags = array_udiff($tags_result, $post_tags_result, 'foo'); 

but result return common value: tag 1. expect tag 4 , tag 9.

    array (size=3)   0 =>      object(stdclass)[8]       public 'id_tag' => string '2' (length=1)       public 'tag' => string 'tag 1' (length=5)   1 =>      object(stdclass)[9]       public 'id_tag' => string '5' (length=1)       public 'tag' => string 'tag 4' (length=5)   3 =>      object(stdclass)[11]       public 'id_tag' => string '7' (length=1)       public 'tag' => string 'tag 9' (length=5) 

as alternative, gather tags needed excluded first. after filter thru array_filter , desired result. rough example:

$tags = array(); foreach($post_tags_result $t) {     $tags[] = $t->tag; // gather tags } // filter array using gathered tags $result = array_filter($tags_result, function($v) use($tags){     return !in_array($v->tag, $tags); }); 

sample output