From: jzakiya@...
Date: 2005-06-27T13:40:39+09:00
Subject: Re: I saw the beauty of Ruby Re: 1. Ruby result: 101 seconds , 2. Java result:9.8 seconds, 3. Perl result:62 seconds

> class Integer
> def primes
> f=2
> p=[] if self <2
> p=[2] if self >=2
> 3.step(self, 2) do |i|
> r = Math.sqrt(i).to_i
> p.each { |f| break if (i%f).zero? or f > r}
> p.push(i) if (i%f).nonzero?
> end # end the do block
> return p
> end
> end

To make shorter/clearer(?) replace

     p=[] if self <2
     p=[2] if self >=2

with

     p = self > 1 ? [2] : []