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 something similar for.

   a = Array.new(5, 1)

   a.each_with_index do |x, i|
     if i == 0
       print x+1
     elsif i == (a.length - 1)
       print x*10
     else
        print x
     end
   end

Pardon the ugliness, but this gets at what one might want... is there a ruby way to do something to the first and last of a loop?

[EDIT] I think ideally this would be an extension on Array with parameters (array instance, all elements function, first elements function, last elements function)... but I'm open to other thoughts.

Answer 1

You could grab the first and last elements and process them differently, if you like.

first = array.shift
last = array.pop
process_first_one
array.each { |x| process_middle_bits }
process_last_one