how to check if PHP variable contains non-numbers?

Question

I just want to know the method to check a PHP variable for any non-numbers and if it also detects spaces between characters? Need to make sure nothing weird gets put into my for

Answer 1

This will return true if there are non-numbers in the string. It detects letters, spaces, tabs, new lines, whatever isn't numbers.

preg_match('#[^0-9]#',$variable)