Siep Korteling <s.korteling@[...].com>  wrote:

>  Hash.new(0) and the block form of Hash.new{_smart_stuff_}  come in
>  really handy while reading in a hash.
>  When the reading is done however, my hash serves to provide data. At
>  that stage, the default_value behaviour gets in the way. For instance,
>  if the hash contains the number of goals for soccerplayers, I don't want
>  the hash to return value "0" for the key "Wolfgang Amadeus Mozart"; by
>  then I want plain old Nil, or "No data available".
>  
>  failed experiment:
>  
>  Class Hash
>    def default_proc
>      Nil
>    end
>  end
>  
>  How can Hash.new behaviour be changed?
>  
>  regards,
>  Siep

h = Hash.new.merge(h)

So for example:

h = Hash.new(0)
h[:a] += 2
h[:a] += 1
h[:b] += 4
p h #=>  {:a=>3, :b=>4}

h = Hash.new.merge(h)
p h[:c] #=>  nil, it's now returning plain old nil

m.
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