From: Gavri Fernandez <gavri.fernandez@...>
Date: 2005-02-14T02:02:40+09:00
Subject: Re: "Joining" strings which may be nil (or) Handling Option hashes

On Mon, 14 Feb 2005 01:44:57 +0900, Robert Klemme <bob.news@gmx.net> wrote:
> 
> "Gavri Fernandez" <gavri.fernandez@gmail.com> schrieb im Newsbeitrag
> news:e3ecfac705021308253ae8704e@mail.gmail.com...

> Lots of, here are some:
> 
> >> opts = {"title"=>"ruby", "author"=>"dave", "publisher"=>"oreilly",
> >> "foo"=>nil}
> => {"title"=>"ruby", "author"=>"dave", "foo"=>nil, "publisher"=>"oreilly"}
> >> opts.select{|k,v|v}
> => [["title", "ruby"], ["author", "dave"], ["publisher", "oreilly"]]
> >> opts.select{|k,v|v}.map{|k,v| "#{k}=#{v}"}.join(" and ")
> => "title=ruby and author=dave and publisher=oreilly"
> 
> Here's a more efficient variant - using #inject of course :-)
> 
> >> opts.inject(nil){|s,(k,v)| v ? (s ? s << " and " : "") << k << "=" << v :
> >> s}
> => "title=ruby and author=dave and publisher=oreilly"


This is the solution I hit upon right after I sent my mail. Please
critique while I try to understand your solutions :)

def get_query(options)
    query_fragments = []
    options.each do |key, value|
        query_fragments.push("#{key.id2name}:#{value}")
    end
    query = query_fragments.join(" and ")
end

Thanks Robert
-- 
Gavri
---------------------------------------------------
I blog here: http://gavri.blogspot.com