Magic First and Last Indicator in a Loop in Ruby/Rails?

Question

Ruby/Rails does lots of cool stuff when it comes to sugar for basic things, and I think there\'s a very common scenario that I was wondering if anyone has done a helper or s

Answer 1

I see a lot of hacks here that are pretty close, but all heavily dependent on the given iterator having a fixed size and NOT being an iterator. I'd like to also propose saving the previous element as you iterate through to know the first/last element that was iterated over.

previous = {}
elements.each do |element|
  unless previous.has_key?(:element)
    # will only execute the first time
  end

  # normal each block here

  previous[:element] = element
end

# the last element will be stored in previous[:element]