From: piir@... (Todd Gardner)
Date: 2004-06-27T23:58:00+09:00
Subject: Re: rounding to n decimal digits

David Garamond <lists@zara.6.isreserved.com> wrote in message news:<40DE9C9F.3030204@zara.6.isreserved.com>...
> I often do this:
> 
>   class Float
>     def round_n(n=0)
>       raise FloatDomainError unless self.finite?
>       raise ArgumentError unless n.class == Fixnum && n >= 0
>       sprintf("%.#{n}f", self).to_f
>     end
> 
>     def ceil_n(n=0)
>       raise FloatDomainError unless self.finite?
>       raise ArgumentError unless n.class == Fixnum && n >= 0
>       (self*10**n).ceil.to_f / 10**n
>     end
> 
>     def floor_n(n=0)
>       raise FloatDomainError unless self.finite?
>       raise ArgumentError unless n.class == Fixnum && n >= 0
>       (self*10**n).floor.to_f / 10**n
>     end
>   end
> 
> However I can't help get the feeling that Ruby already has something 
> like this. Did I indeed miss it?

And you can combine the lines...

puts a=1.1568753256
puts digits=3
puts ((a).*10**digits).round.to_f/10**digits

Todd