Declaring an integer Range with step != 1 in Ruby

Question

UPDATE 2: For posterity, this is how I\'ve settled on doing it (thanks to Jorg\'s input):

100.step(2, -2) do |x|
    # my code
end


        

Answer 1

You can't declare a Range with a "step". Ranges don't have steps, they simply have a beginning and an end.

You can certainly iterate over a Range in steps, for example like this:

(2..100).step(2).reverse_each(&method(:p))

But if all you want is to iterate, then what do you need the Range for in the first place? Why not just iterate?

100.step(2, -2, &method(:p))

This has the added benefit that unlike reverse_each it does not need to generate an intermediate array.

Answer 2

This question answers yours: about ruby range?

(2..100).step(2) do |x|
    # your code
end

Answer 3

I had similar issue here are the various ways I found to do the same SIMPLE thing I used step in the end because it allowed for NEGATIVE and FRACTIONAL increments and I had no conditions, other than the bounds to look for

  case loop_type

    when FOR
      # doen't appear to have a negative or larger than 1 step size!
      for kg in 50..120 do
        kg_to_stones_lbs(kg)
      end

    when STEP
      120.step(70,-0.5){ |kg|
        kg_to_stones_lbs(kg)
      }

    when UPTO
      50.upto(120) { |kg|
        kg_to_stones_lbs(kg)
      }

    when DOWNTO
      120.downto(50){ |kg|
        kg_to_stones_lbs(kg)
      }

    when RANGE
      (50..120).reverse_each{ |kg|
        kg_to_stones_lbs(kg)
      }

    when WHILE
      kg = 120
      while kg >= 50
        kg_to_stones_lbs(kg)
        kg -= 0.5
      end
  end

O/P:

92.0kg - 14st 7lbs

91.5kg - 14st 6lbs

91.0kg - 14st 5lbs

90.5kg - 14st 4lbs

90.0kg - 14st 2lbs

89.5kg - 14st 1lbs

89.0kg - 14st 0lbs

88.5kg - 13st 13lbs

88.0kg - 13st 12lbs