Online PHP editor | output for VFq83

<?php $data = array("S28000000000000003" => 'ABC',"S28000000000000001" => 'PQR'); $keys = array("S28000000000000003","S28000000000000001"); $keysDerived = array_keys($data); var_dump($keys == $keysDerived, $keys === $keysDerived); var_dump(in_array("28000000000000003", array_keys($data), true)); var_dump(in_array("28000000000000003", $keysDerived)); var_dump(in_array("28000000000000003", $keys, true)); var_dump(in_array("28000000000000003", $keys)); foreach ( $data as $k => $d ) { foreach ( $keys as $key ) { if ($key == $k) { var_dump($k, "=", $key); } if ($key === $k) { var_dump($k, "===", $key); } } }