PHP variable names with integer increments

In a loop I needed to create / lookup variables that end with a numeric increment. What I found was I can use the following:

for ($x = 1; $x <= 10; $x++) {
    if (${'variableName'.$x} !='') {
		echo(${'quantQ'.$x});
	}
}

for ($x = 1; $x <= 10; $x++) {

if (${'variableName'.$x} !='') {

echo(${'quantQ'.$x});

}