From: "Wesley J. Landaker" <wjl@...>
Date: 2003-08-28T05:48:59+09:00
Subject: Re: sorting on hash contents

Apparently, Mark Probert recently wrote:
>
> Hi, all.
>
> Say I have a hash of 4 elements, val[1..3] and name
>
>   h["a"] = "1,2,3,fred"
>   h["b"] = "4,1,2,jack"
>   h["c"] = "3,3,4,jill"
>
> How do I define:
>
>   def sort_hash(field="val1")
>     h.each { |key, data|
>       (val1, val2, val3, name) = data.split(/,/)
>     # etc..
>   end
>
> elegantly?
>
> One possibility is to write it out to a tempfile and use
> the external `sort` command.  Is there an easy pure-ruby
> solution?

Not a full answer (no time right now), but run this in irb and it should
should give you some ideas:

h = {}
h["a"] = "1,2,3,fred"
h["b"] = "4,1,2,jack"
h["c"] = "3,3,4,jill"
h.to_a
h.to_a.sort_by { |el| el[1].split(/,/)[0] }
h.to_a.sort_by { |el| el[1].split(/,/)[1] }
h.to_a.sort_by { |el| el[1].split(/,/)[2] }
h.to_a.sort_by { |el| el[1].split(/,/)[3] }

Wes