I don't know if you want it to work with octal or hex but this will work for decimal.

$word =~ /^-?(\d*)\.?(\d*)$/ && (length($1) || length($2));
[download]

What's with the length checks? ".807" and "30." are valid numbers whereas "." is not. Hope this helps.

antirice    
The first rule of Perl club is - use Perl
The ith rule of Perl club is - follow rule i - 1 for i > 1