ruby - Modify multidimensional array of symbols -

at moment have like:

arr = [   :name,   :address,   cards_attributes: [     :last_name,     :first_name,     phones_attributes: [       :number,       :_destroy     ],     emails_attributes: [       :number,       :_destroy     ],     ...   ] ] 

... , want turn like:

arr = [   :id, # <- new!   :name,   :address,   cards_attributes: [     :id, # <- new!     :last_name,     :first_name,     phones_attributes: [       :id, # <- new!       :number,       :_destroy     ],     emails_attributes: [       :id, # <- new!       :number,       :_destroy     ],     ...   ] ] 

i know can add new symbol first level arr.push(:id) how add elements sub hashes?

def add_id(collection)   collection.unshift(:id) if collection.respond_to?(:unshift)    collection.each |key, value|     add_id(key)   if key.respond_to?(:each)     add_id(value) if value.respond_to?(:each)   end end 

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edit: following update

"my question more how elegantly access sub hashes?"

we can use same general idea. didn't specify operation executed on hashes, method expect block:

def traverse(collection)   yield collection if collection.is_a? hash    collection.each |key, value|     traverse(key)   if key.respond_to?(:each)     traverse(value) if value.respond_to?(:each)   end end  traverse(arr) { |hash| puts hash }