Verifique se a matriz tem valor php
$myArr = [38, 18, 10, 7, "15"];
echo in_array(10, $myArr); // TRUE
echo in_array(19, $myArr); // TRUE
// Without strict check
echo in_array("18", $myArr); // TRUE
// With strict check
echo in_array("18", $myArr, true); // FALSE
Allen