From: Robert Klemme <shortcutter@...>
Date: 2011-04-20T17:50:55+09:00
Subject: Re: Can I check contain value in hash?

On Wed, Apr 20, 2011 at 10:33 AM, Brian Candler <b.candler@pobox.com> wrote:
> For some applications,
>
>  dict[key] << val
>  dict[key].uniq!
>
> will be good enough. But this will still slow down if the number of
> values in the list gets large, in which case a hash of hashes would be
> better:
>
>  dict[key] ||= {}
>  dict[key][val] = true
>
> To get the values, you'd then use dict[key].keys (which in ruby 1.8
> would be in an arbitrary order, and in 1.9 would be in order of first
> insertion)

My first choice would be to use Set and not Hash as values.

require 'set'

dict = Hash.new {|h,k| h[k] = Set.new}

dict[key] << val
dict[key].include? val

Kind regards

robert

-- 
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