From: "David A. Black" <dblack@...>
Date: 2009-08-10T03:32:46+09:00
Subject: Re: Generate binary sequences of length n?

Hi --

On Mon, 10 Aug 2009, Tom Best wrote:

> I'm rather new to Ruby.  I feel this should be very simple, but I'm
> having trouble:
>
> I'd like to write a script to work through all possible binary sequences
> of length n.
>
>
>
> The script would work as follows:
>
> mylength = 4
> resultz = binary_seq_generator(mylength)
> puts "#{resultz}"
>
> #resultz, not necessarily in this order:
> ["0000","0001","0010","0011","0100","0101","0110","0111","1000","1001","1010","1011","1100","1101","1110","1111"]

Try this:

def binary_seq_generator(n)
   (0...(1 << n)).map {|e| "%0#{n}d" % e.to_s(2) }
end

Doesn't necessarily roll off the fingers as readily as some Ruby
idioms do :-) But I think all or most of what you need is there, and
there are some interesting bits to it.


David

-- 
David A. Black / Ruby Power and Light, LLC / http://www.rubypal.com
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