From: Harry Kakueki <list.push@...>
Date: 2011-06-04T18:06:15+09:00
Subject: Re: Best way to replace hash keys

On Fri, Jun 3, 2011 at 11:27 PM, Alex Allmont
<Alex.Allmont@naturalmotion.com> wrote:
> What is the most optimal and neatest way to replace keys in a hash given a particular condition?
>
> I'm currently using delete_if and putting replacement values into a new hash before merging them back into the original hash.  Another approach would to simply rebuild a whole new hash.
>
>  # Contrived example: given searchReplacePairs hash of { search => replace } pairs,
>  # convert any String keys to a Regexp.
>  newPairs = { }
>  searchReplacePairs.delete_if do |search, replace|
>    if search.class == String
>      newPairs[Regexp.new(search)] = replace
>    end
>  end
>  searchReplacePairs.merge! newPairs
>
> Many thanks,
> Alex
>
>
>

I won't claim this is the best way but it may be worth a look.
Is it doing what you want or did I misunderstand?


a = {"ONE"=>"1",2=>"2","THREE"=>"3"}

t = a.to_a.transpose
b = Hash[*(t[0].map{|x| x.class==String ? Regexp.new(x) :x}.zip(t[1])).flatten]
p b #>   {/ONE/=>"1", 2=>"2", /THREE/=>"3"}




Harry