สอบถามหน่อยครับ วิธีเเยก "_" "."

function teacher_type($teacher) {
	return strpos($teacher, '.') !== false ? 'Teacher' : (strpos($teacher, '_') !== false ? 'Parttime_Teacher' : 'Unknown');
}

$x = "name.s";
$y = "name_s";
$z = "name-s";

$names = [$x, $y, $z];
foreach ($names as $name) {
	$type = teacher_type($name);
	echo "\"$name\" - $type<br>";
}