One of the ways to get intersection of two arrays is as follows:

<?php
function arrayIntersect( $primary_array, $secondary_array ) {
    
    if ( !is_array( $primary_array ) || !is_array( $secondary_array ) ) {
        return false;
    }
    
    if ( !empty( $primary_array ) ) {
        
        foreach( $primary_array as $key => $value ) {
            
            if ( !isset( $secondary_array[$key] ) ) {
                unset( $primary_array[$key] );
            } else {
                if ( serialize( $secondary_array[$key] ) != serialize( $value ) ) {
                    unset( $primary_array[$key] );
                }
            }
            
        }
        
        return $primary_array;
        
    } else {
        return array();
    }
    
} 
?>

It would pay attention to both keys and values even if values would be arrays as well. One important note is that if value of $primary_array is yet another array, its order of key & value pairs becomes important for matching.

# ket tomb kulcs alapu metszetet szamitja ki, az erteken is ellenorzest vegez
#
# calculating (key base) intersection of arrays (value are checked)
# use: $result_array = array_intersect_assoc($a1, $a2, $a3,..);
#
##
# original code by [jochem at iamjochem dawt com] : array_diff_keys()

<?php
function array_intersect_assoc() {

    $args = func_get_args();
    $res = $args[0];

    for ($i=1;$i<count($args);$i++) {
        if (!is_array($args[$i])) {continue;}

        foreach ($res as $key => $data) {
            if ( (!array_key_exists($key, $args[$i])) || ( (isset($args[$i][$key])) && ($args[$i][$key] !== $res[$key]) ) ) {
                unset($res[$key]);
            }
        }
    }

    return $res;
}

?>

<?php
$array1 = array("a"=>"green", "b"=>"brown", "c"=>"blue", "red");
$array2 = array("a"=>"green", "b"=>"yellow", "c"=>"yellow", "red");
$a = array('a'=>'green', 'b'=>'brown', 'c'=>'yellow');
$b = array('a'=>'green', 'b'=>'brown', 'c'=>'yellow', 'e'=>'yellow');

$result_array = array_intersect_assoc($a, $b, $array1, $array2);
?>

$args array will look like:

(
    0 => 
        (
            a => green
            b => brown
            c => yellow
        )

    1 => 
        (
            a => green
            b => brown
            c => yellow
            e => yellow
        )

    2 => 
        (
            a => green
            b => brown
            c => blue
            0 => red
        )

    3 => 
        (
            a => green
            b => yellow
            c => yellow
            0 => red
        )

)

$result_array will look like:

(
    a => green
)