Ruby inject with index and brackets

Question

I try to clean my Code. The first Version uses each_with_index. In the second version I tried to compact the code with the Enumerable.inject_with_index-constr

Answer 1

Seems like there already some answers given with good explanation. I want to add some information regards the clear and readable.

Instead of the solution you chose, it is also a possibility to extend Enumerable and add this functionality.

module Enumerable
  # The block parameter is not needed but creates more readable code.
  def inject_with_index(memo = self.first, &block)
    skip = memo.equal?(self.first)
    index = 0
    self.each_entry do |entry|
      if skip
        skip = false
      else
        memo = yield(memo, index, entry)
      end
      index += 1
    end
    memo
  end
end

This way you can call inject_with_index like so:

# m = memo, i = index, e = entry
(1..3).inject_with_index(0) do |m, i, e|
  puts "m: #{m}, i: #{i}, e: #{e}"
  m + i + e
end
#=> 9

If you not pass an initial value the first element will be used, thus not executing the block for the first element.