array iteration problem

rb_array_iterate.rb

def add1(arr, val, n)
  # how many times are we going to increment
  increment_count = n == 0 ? arr.length : n.abs
  # are we going up or down the array
  indices = n < 0 ? (-1..-arr.length) : (0...arr.length)
  # iterate and update the array in place
  indices.each do |index|
    if (arr_value = arr[index]) == val
      arr[index] = arr_value + 1
      # decrement and check the count all in one go
      break if (increment_count -= 1) == 0
    end
  end
  # nothing to return since the array is updated in place
end

you get an undefined arr_value in this

Woops - try it now. Removed the then and turend the breaker into one line

and you need to return the array at the end of the method

def add1(arr, val, n)
  increment_count = n == 0 ? arr.length : n.abs
  indices = n < 0 ? (-1..-arr.length) : (0...arr.length)

  indices.each do |index|
    arr[index] = arr[index] + 1 if val == arr[index]

    break if (increment_count -= 1) == 0
  end
  arr
end

Yes, to be a true rubyist one would need to do that. Because modifications are in place, one could also just add ! to the method definition.