Hash#[]

ruby-talk
1

Am I the only one who thinks this would be a natural behavior for Hash#[]?

   hsh = {:foo => 'FOO', :bar => 'BAR', :baz => 'BAZ'}
   hsh[:foo] #=> "FOO"
   hsh[:foo, :baz] #=> ["FOO", "BAZ"]

That would enable us to do the following

   def initialize(opts = {})
     @host, @user, @pass = opts[:host, :user, :pass]
   end

Since the old functionality isn't changed, it would be backwards compatible.

Implementation:

   class Hash
     def [](*keys)
       if keys.length == 1
         fetch(keys.first, nil)
       else
         keys.map{|key| fetch(key, nil)}
       end
     end
   end

Cheers,
Daniel

2

Daniel Schierbeck wrote:

  class Hash
    def (*keys)
      if keys.length == 1
        fetch(keys.first, nil)
      else
        keys.map{|key| fetch(key, nil)}
      end
    end
  end

The implementation needs a little update:

   class Hash
     def (*keys)
       if keys.length == 1
         fetch(keys.first, default(keys.first))
       else
         keys.map{|key| fetch(key, default(key))}
       end
     end
   end

That should take care of default values and such.

Daniel

3

No, you're not. However, there is Hash#values_at() which already does
the same thing.
(Can anyone remind me why Hash# doesn't allow *args?)

Regards,
Sean

···

On 6/11/06, Daniel Schierbeck <daniel.schierbeck@gmail.com> wrote:

Am I the only one who thinks this would be a natural behavior for Hash#?

   hsh = {:foo => 'FOO', :bar => 'BAR', :baz => 'BAZ'}
   hsh[:foo] #=> "FOO"
   hsh[:foo, :baz] #=> ["FOO", "BAZ"]

4

Daniel Schierbeck wrote:

  class Hash
    def (*keys)
      if keys.length == 1
        fetch(keys.first, default(keys.first))
      else
        keys.map{|key| fetch(key, default(key))}
      end
    end
  end

This was much simpler in my head...

   class Hash
     def (*keys)
       if keys.length == 1
         fetch(keys.first) rescue default(keys.first)
       else
         keys.map{|key| fetch(key) rescue default(key)}
       end
     end
   end

Daniel

5

Seems not too bad. Or am I missing something?

···

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6

Hash#values_at does what I want. Never mind.

!#%¤#!"%(§%§§"¤/"%/(!!!

Daniel