Question

How do I set a starting offset for each loop in ruby?
I want the loop to begin from a[3] instead of a[0]. How do I set that?

a = [ab, cd, ef, gh, hi, jk]

a.each do |i|
#some stuff
end

Answer 1

Another, possibly more direct and readable possibility is to use Array#drop:

a.drop(3).each do |i|
  # do something with item i
end

Now this really shines if combined with other methods inherited from Enumerable, so chances are there’s a better alternative to your imperative each loop. Say you want to filter the extracted slice and transform it afterwards:

a = [0,1,2,3,4,5,6,7]
a.drop(3).select(&:even?).map { |x| x * 2 }
# => [8, 12]

Or say you want to print a list of all the values:

a = ["1", "2", "3", "4", "5"]
puts a.drop(3).join("\n")

Output:

4
5

These features inherited from functional programming are what makes Ruby so strong 🙂