From: Robert Klemme <bob.news@...>
Date: 2003-09-16T05:08:35+09:00
Subject: Re: performance and style advice requested


"Robert Feldt" <feldt@ce.chalmers.se> schrieb im Newsbeitrag
news:oprvjzzqcmoglyup@mail1.telia.com...
> Robert Feldt <feldt@ce.chalmers.se> skrev den Tue, 16 Sep 2003 03:14:05
+0900:
>
> > @facts = [1]
> > def fact(n)
> > @facts[n] ||= (@facts.last..n).inject(1) {|f, i| @facts[i] = i * f}
> > end
> >
> Oops, it should be
>
> @facts = [1]

IMHO rather:
@facts = [0,1]

> def fact(n)
>   @facts[n] ||= (@facts.length..n).inject(@facts.last) {|f, i| @facts[i] =
i * f}
> end

And, I think there's a subtle bug with the inject parameter.  Another
version:

def fact(n)
  @facts ||= [0,1]
  @facts[n] ||= (@facts.length..n).inject(@facts[-1]) {|f, i| @facts[i] = i
* f}
end

And: Dave, thanks for this inspiring reduction!  I haven't grown familiar to
inject() yet...

Kind regards

    robert