From: Logan Capaldo <logancapaldo@...>
Date: 2007-05-04T22:55:34+09:00
Subject: Re: Array to Hash

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On 5/3/07, William James <w_a_x_man@yahoo.com> wrote:
>
> On May 3, 11:41 am, Josselin <josse...@wanadoo.fr> wrote:
> > is it possible to convert easily an Array like this one :
> >
> > [ nil, "b", nil, nil, nil , "f", "g", nil, nil, "j"]
> >
> > to an Hash like this one
> >
> > { 1 => "b", 5 => "f", 6 => "g", 9 => "j"  }
> >
> > where the key is the position of  a value if not nil .. ?
>
> We don't need no stinkin' loops!
>
> >> a=[ nil, "b", nil, nil, nil , "f", "g", nil, nil, "j"]
> => [nil, "b", nil, nil, nil, "f", "g", nil, nil, "j"]
> >> h=Hash[*(0...a.size).zip(a).reject{|x|x[1]==nil}.flatten]
> => {5=>"f", 6=>"g", 1=>"b", 9=>"j"}


Indeed,
require 'enumerator'
a.enum_with_index.reject { |v, k| v.nil?  }.inject({}) { |h, (v,k)|
h.update(k => v) }

PS. my solution preserves nested arrays, etc. in the original dataset

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