Question

So basically I need to return the value of the previous Point.

e.g. I’m on the third point. I need the point.kilometric_position of the second point.

Part of my controller action is pasted here. Thanks in advance!

def calculate
  @points = Point.all

  # loop through all the points
  @points.each do |point|
    # calculate the current kilometric position
    if point.kilometric_position.nil?
      # kilometric_position = previous_kilometric_position + distance
    end
  end
end

Answer 1

@points.each_with_index do |point, i|
  previous_point = @points[i-1] unless i==0

  next unless previous_point
  distance = point.distance_to(previous_point)
  # do something with distance
end