array_intersect(): Intersection of two or more arrays

$new_array = array_intersect ($array1, $array2,....);

Example 1

$first=array(1,2,3,4);
$second=array(1,2,3,5);
$result1=array_intersect($first,$second);
while (list ($key, $val) = each ($result1)) {
echo "$key -> $val <br>";
}

0 -> 1 
1 -> 2 
2 -> 3 

Example 2

$first=array('One' =>1,'Two'=>2,'Three'=>3,'Four'=>'Fourth');
$second=array('One'=>1,'Two'=>2,'Third'=>3);

$result1=array_intersect_assoc($first,$second);
while (list ($key, $val) = each ($result1)) {
echo "$key -> $val <br>";
}

One -> 1 
Two -> 2 
Three -> 3 

Example: Associative Arrays

$array1 = ["a" => "green", "b" => "red", "c" => "blue"];
$array2 = ["b" => "green", "c" => "yellow"];
$result = array_intersect($array1, $array2);
print_r($result);  // Output: Array ( [a] => green )

Example: Case-Insensitive Intersections

$array1 = ["Red", "Green", "Blue"];
$array2 = ["red", "green"];
$result = array_intersect(array_map('strtolower', $array1), array_map('strtolower', $array2));
print_r($result);  // Output: Array ( [0] => red [1] => green )