From: William James <w_a_x_man@...>
Date: 2005-02-15T10:19:54+09:00
Subject: Re: "Joining" strings which may be nil (or) Handling Option hashes


William James wrote:
> Robert Klemme wrote:
> >
> > 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"
>
>
> I prefer this:
>
> opts.to_a.map{|x| x.join('=') if x[1]}.compact.join(' and ')
>
> ---->  "title=ruby and author=dave and publisher=oreilly"

Too prolix.  Better:

opts.map{|x| x.join('=') if x[1]}.compact.join(' and ')

Here are the stages through which the data travels:

{"title"=>"ruby", "author"=>"dave", "foo"=>nil, "publisher"=>"oreilly"}
["title=ruby", "author=dave", nil, "publisher=oreilly"]
["title=ruby", "author=dave", "publisher=oreilly"]
"title=ruby and author=dave and publisher=oreilly"