From: Michael Fellinger <m.fellinger@...>
Date: 2006-11-18T18:50:34+09:00
Subject: Re: ruby equivalent PHP function is_numeric?

On 11/18/06, Wilson Bilkovich <wilsonb@gmail.com> wrote:
> On 11/17/06, David Vallner <david@vallner.net> wrote:
> > ara.t.howard@noaa.gov wrote:
> > > On Sat, 18 Nov 2006, Josselin wrote:
> > >
> > >> After reading completely my Ruby book, I cannot find a function
> > >> equivalent to the PHP  is_numeric? to test a String
> > >>
> > >> myString.is_numeric?   (check only digits and dot character)   =>
> > >> return true or false
> > >>
> > >> does it exist ? or it's more complicated than that ? (need to build a
> > >> regex... ?)
> > >>
> > >> thanks
> > >>
> > >> joss
> > >
> > >
> > >
> > >   harp:~ > cat a.rb
> > >   def is_numeric?(n) Float n rescue false end
> > >
> >
> > def is_numeric?(n) begin Float n; return true rescue false end
> >
> > Predicate methods not returning a boolean make my skin crawl even if
> > it's all the same difference for conditionals.
> >
>
> Or the golf version:
> def is_numeric?(n)
>   !!Float(n) rescue false
> end

and the handy version, if you actually don't care but want something
nice instead:

class String
  def to_numeric
    Integer(self) rescue Float(self) rescue nil
  end
end