From: Brian Mitchell <binary42@...>
Date: 2005-09-20T17:24:59+09:00
Subject: Re: ruby idiom for python's for/else while/else

On 9/20/05, Pit Capitain <pit@capitain.de> wrote:
> William James schrieb:
> > ...
> > (2...50).select{|n|(2..Math.sqrt(n).to_i).select{|x|n % x == 0}.empty?}
> >      -->
> > [2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47]
>
> Should be a little bit more efficient:
>
>    (2...50).reject{|n|(2..Math.sqrt(n)).find{|x|n % x == 0}}
>
> It's not what the OP wanted, though.
>
> Regards,
> Pit
>

Yeah. I just thought I would post it. Mostly equivalent to what he was
doing but quite different in what tools were used. Yours is much more
elegant either way.

If I was serious about the prime numbers I would have built a
quadratic sieve of some sort. I also hate for-loops (in most cases).
;)

Brian.