From: Robert Klemme <shortcutter@...>
Date: 2007-11-28T01:53:22+09:00
Subject: Re: Most elegant way to do this?

2007/11/27, Brian Adkins <lojicdotcom@gmail.com>:
> On Nov 26, 7:17 pm, rbysam...@gmail.com wrote:
> > Are there any more elegant, concise, pithy, and more Rubyish ways of
> > doing this?
> >
> > def roll(number_of_dice)
> >     sum = 0
> >     number_of_dice.times do
> >         sum += rand(5).next
> >     end
> >     sum
> > end
> >
> > Thanks in advance!
>
> As others have pointed out, you need rand(6).next to get (1..6);
> otherwise, it's hard to improve on what you have here. This is a
> simple, iterative mathematical function. I personally don't think
> using map, inject, etc. is more "Rubyish" in this context, just 2 to 3
> times slower.
>
> The interface is "roll n" regardless of the underlying implementation,
> so you might as well make it fast.
>
> One style improvement might be to use a one line block:
>
> def roll num_dice
>   sum = 0
>   num_dice.times { sum += rand(6).next }
>   sum
> end
>
> You can make it ~10% faster (with the loss of some readability) by not
> invoking next each time and just summing at the end:
>
> def roll num_dice
>   sum = 0
>   num_dice.times { sum += rand(6) }
>   sum + num_dice
> end

I guess there is even more room for improvement by doing this:

def roll num_dice
  sum = roll num_dice
  num_dice.times { sum += rand(6) }
  sum
end

SCNR ;-)

robert

-- 
use.inject do |as, often| as.you_can - without end