From: Phrogz <phrogz@...>
Date: 2010-01-02T13:50:14+09:00
Subject: Re: Rounding float in ruby via .round

On Jan 1, 9:32 pm, Phrogz <phr...@mac.com> wrote:
> You could do (untested on 1.8):
>
> if Float.instance_method(:round).arity == 0
>   class Float
>     alias_method :_orig_round, :round
>     def round( decimals=0 )
>       factor = 10**decimals
>       (self*factor)._orig_round / factor
>     end
>   end
> end

Bah, should have tested. Of course the original round returns a
fixnum, so dividing by the factor at that point really doesn't do what
I had intended.

Here are a few alternatives. Poke fun at them and/or benchmark as you
see fit:

if Float.instance_method(:round).arity == 0
  class Float
    alias_method :_orig_round, :round
    def round( decimals=0 )
      factor = 10.0**decimals
      (self*factor)._orig_round / factor
    end
  end
end

if Float.instance_method(:round).arity == 0
  class Float
    alias_method :_orig_round, :round
    def round( decimals=0 )
      factor = 10**decimals
      (self*factor)._orig_round.to_f / factor
    end
  end
end

if Float.instance_method(:round).arity == 0
  class Float
    alias_method :_orig_round, :round
    def round( decimals=0 )
      factor = 10**decimals
      (self*factor)._orig_round / factor.to_f
    end
  end
end