can I call a variable... using variables?

So here's what I'm trying to do: I have a form submitting dozens of variables called var1, var2, var3, ....... and on and on. I want to check the value of each of these variables: for($i = 1;$i < 100; $i++) { if($var$i > 0) echo "Yup. $var$i is greater than 0"; } I get a parse error when trying to run this code. Can I not use $i to call the $var1, $var2, etc. variables? Is there another way of doing this? Thanks, Joseph