How do I tell if a variable has a numeric value in Perl?

Question

Is there a simple way in Perl that will allow me to determine if a given variable is numeric? Something along the lines of:

if (is_number($x))
{ ... }
         


        

Answer 1

if ( defined $x && $x !~ m/\D/ ) {} or $x = 0 if ! $x; if ( $x !~ m/\D/) {}

This is a slight variation on Veekay's answer but let me explain my reasoning for the change.

Performing a regex on an undefined value will cause error spew and will cause the code to exit in many if not most environments. Testing if the value is defined or setting a default case like i did in the alternative example before running the expression will, at a minimum, save your error log.