php check if item in array

$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

in_array ( mixed $needle , array $haystack [, bool $strict = FALSE ] ) : bool
  
// Without strict check
echo in_array("18", $myArr); // TRUE
// With strict check
echo in_array("18", $myArr, true); // FALSE

if (!empty($data_days) && in_array(1, $data_days, true)){ // use numeric value 1, not string

$allowedFileType = ['application/vnd.ms-excel','text/xls','text/xlsx','application/vnd.openxmlformats-officedocument.spreadsheetml.sheet'];
  
if(in_array($_FILES["file"]["type"],$allowedFileType))