If I can come up with so many different interpretations of "is this string an integer" ((tye)Re: Integer detection concept), just think how many interpretations of "is this string a number" covers.

First you need to decide which of the many meanings you are dealing with and then you can decide which of probably several ways you can try to get that answer. If someone offers to tell you how to determine is a string "is a number" without forcing you to be a lot more specific, then are likely answering the wrong question for you. (:

Though, I do think that Perl's internal looks_like_number() might be the right answer for several common meanings of that question. I really need to find the time to get an interface to that available from CPAN and included in a future version of the core. /: