From: Andrew Wagner <wagner.andrew@...>
Date: 2011-02-03T00:17:47+09:00
Subject: Re: Soliciting some help with inject method

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Here's one simple way to do it:

hash = array.inject({}) do |result, array|
  key,val = array
  if result[key].nil?
    result[key] = [val]
  else
    result[key].push val
  end
  result
end

On Wed, Feb 2, 2011 at 9:56 AM, Edmond Kachale <
edmond.kachale@baobabhealth.org> wrote:

> Rubysters,
>
> I think I am not wrong if I can solicit some knowledge. :-)
>
> Can any one help modify this code?
>
> I have:
> array = [['a', 1], ['b', 2], ['a',2], ['c',4], ['d', 5], ['b',4]]
>
> I want to create a hash using inject method:
> >> hash = {'a' => [1, 2], 'b' => [2, 4], 'c' => [4], 'd' => [5]}
>
> The following code gives: {"a"=>[2], "b"=>[4], "c"=>[4], "d"=>[5]}
>
> hash  = array.inject({}) do |result, array|
> new_hash = {}
> new_hash[array.first] = [array.last]
> result.merge!(new_hash)  # I have tried result.update(new_hash) but it
> fails
> too
> result
> end
>
> Here is a console friendly version of the same:
> hash  = array.inject({}){|result, array| new_hash = {};
> new_hash[array.first] = [array.last]; result.merge!(new_hash); result;}
>
> Thanks in advance,
>
> ---
> Edmond
> Software Developer | Baobab Health Trust (http://www.baobabhealth.org/) |
> Malawi
>
> Cell:  +265 999 465 137 | +265 881 234 717
>
> *I wish you a Merry Christmas and a Prosperous New Year 2011!!**
> *
>

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