Ruby array starting at 1 [duplicate]

Question

I have an array with indices 0..n The 0th position is nil. My information starts at position 1. What is a Ruby way of traversing this array and start with position one. Currently what I'm doing is the following:

([email protected]).each do |index|
  do something with @vertices[index]
end

Answer 1

I'm building chemical formula names. And to avoid confusion, I want to store a molecule with 1 Carbon atom in @vertices[1]

Use a Hash instead:

@vertices = {
  1 => 'Molecule with 1 carbon atom',
  2 => 'Molecule with 2 carbon atoms',
  5 => 'Molecule with 5 carbon atoms'
}

@vertices.each do |carbon_atoms, molecule|
  # do something with molecule
end

Answer 2

I'm unsure why you're starting from index 1, as 0 is standard, but the way I would approach this is either:

@vertices[1..-1].each { |element| do_what_you_planned_on_doing }

or

@vertices.each_with_index do |ele, index|
  next if index == 0
  do_what_you_planned_on_doing
end

I prefer the first one. It seems more elegant.