From: James Edward Gray II <james@...>
Date: 2007-03-27T02:45:22+09:00
Subject: Re: Regexp and Prime numbers

On Mar 19, 2007, at 2:07 PM, Tim Pease wrote:

> This is a one-liner Ruby script that will tell you if a given  
> number is prime.
>
> ruby -wle 'puts "Prime" unless ("1" * ARGV[0].to_i) =~
> /^1$|^(11+?)\1+$/' [number]
>
>
> I cannot take credit for this one -- it originally came from Perl. The
> website listed below gives the full explanation of how the regexp
> works.
>
> http://montreal.pm.org/tech/neil_kandalgaonkar.shtml
>
> I highly recommend reading this if you want to flex your regexp  
> muscles today.

Wow, that was just awesome.

James Edward Gray II