Issue #5531 has been updated by Thomas Sawyer.


Probably best to use #[] internally too.

    class Hash
      def [](*keys)
        keys.inject(self) {|container, key| value = container[key]; value ? value : return value}
      end
    end

@Alexey you may have a point. But I suspect it would need to be conditioned off of responding to #to_h or #to_hash instead of using `is_a?(Hash)`.

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Feature #5531: deep_value for dealing with nested hashes
http://redmine.ruby-lang.org/issues/5531

Author: Kyle Peyton
Status: Open
Priority: Normal
Assignee: 
Category: 
Target version: 


This feature request stems from dealing with nested hashes, like the params from a request often dealt with in web frameworks.

Conditional code often needs to be written with multiple logical ANDs in order to achieve what this simple function can:

class Hash
  def deep_value(*ks)
    if ks.size == 1
      return self[ks.shift]
    else
      val = ks.shift
      return (self[val].is_a?(Hash) ? self[val].deep_value(*ks) : nil)
    end
  end
  
  alias dv deep_value
end


deep_value (dv) will simply recurse over a hash given a set of indexes and return the value at the end.

Example:

> foo = {:bar => {:baz => 'blah'}}
> foo.dv(:bar, :baz)
-> 'blah'
> foo.dv(:cats)
-> nil



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