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From: Robert Klemme <shortcutter@googlemail.com>
Newsgroups: comp.lang.ruby
Subject: Re: Updating a Hash Value Based On Same-Key in Another Hash
Date: Mon, 19 Nov 2012 21:19:54 +0100
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On 19.11.2012 16:51, Jeff Nyman wrote:
> Hey all.
>
> I have an issue where I have two hashes. What I'm trying to do is replace a value in the original hash if the second hash has a key matching one of the keys in the first has. To be specific, I have these two hashes:
>
> data = {"study"=>"Lucid Study", "name"=>"Lucid Plan", "studyWillBe"=>"Combination"}
>
> conditions = {"study"=>"((current))"}
>
> What I want to have happen is the data hash should have its "study" key updated since that key is matched in the conditions hash. So I want data to end up like this:
>
> data = {"study"=>"((current))", "name"=>"Lucid Plan", "studyWillBe"=>"Combination"}
>
> I'm having a mental block on this. I got this far:
>
> data = Hash[data.map {|k, v| [conditions[k] || k, v] }]
>
> But that's not quite doing the trick and I'm finding it hard to get the effect I want.
>
> Can anyone point me in the right direction? Much appreciated.

data.keys.each do |k|
   conditions.has_key?(k) and data[k] = conditions[k]
end

keys = data.keys
keys.zip(conditions.values_at(*keys)) do |k,v|
   data[k] = v unless v.nil?
end

Kind regards

	robert

-- 
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/