Question

I have two arrays

1.$ids;

Array
(
    [0] => 2427975642
    [1] => 2397521678
)

2.$c

Array
(
    [48] => 2397521678
    [46] => 461
    [45] => 451
)

Question:
Search values from $ids in $c and return new array with id. Example return 48

Answer 1

$ids = array(   
    2427975642,
    2397521678
);



$c = array(
    48 => 2397521678,
    46 => 461,
    45 => 451
);

$common = array_keys(array_intersect($c, $ids));

print_r($common);