Flatten a Ruby Array without using built-in 'flatten' method [closed]

Answer 1

class Array
  def flattify
    each_with_object([]) do |element, flattened|
      flattened.push *(element.is_a?(Array) ? element.flattify : element)
    end
  end
end

[1,2,3,4,[1,2,3,4],5].flattify # => [1, 2, 3, 4, 1, 2, 3, 4, 5]

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A non-monkey patching Array version:

def flattify(array)
  array.each_with_object([]) do |element, flattened|
    flattened.push *(element.is_a?(Array) ? flattify(element) : element)
  end
end

flattify([1,2,3,4,[1,2,3,4],5]) # => [1, 2, 3, 4, 1, 2, 3, 4, 5]