So I need an argument for if that triggers every 20 new bars. As you can see I have the code ready, but for some dumb reason, I can’t figure out how to trigger it every 20 new bars.

//Input options
highlength = input.int(20, "High Length")
lowlength  = input.int(20, "Low Length")

Tah = ta.highest(highlength)
Tal = ta.lowest(lowlength) 

//color fill
var highhighs = float(na)
var lowlows   = float(na)
var line Linehighhighs =           na
var line Linelowlows   =           na

if 'every 20 new bars i want to plot a line with the highest and lowest values'
    highhighs     := Tah
    lowlows       := Tal
    Linehighhighs :=           line.new(bar_index, highhighs, bar_index, highhighs, color = color.white, width = 2)
    Linelowlows   :=           line.new(bar_index, lowlows, bar_index, lowlows, color = color.white, width = 2)
else
    line.set_x2(Linehighhighs, bar_index)
    line.set_x2(Linelowlows, bar_index)

I really appreciate any help you can provide.

>Solution :

Using the Modulo Operator % on bar_index and comparing the reminder to 0 will trigger the condition every 20 bars:

if bar_index % 20 == 0 
    highhighs     := Tah
    lowlows       := Tal
    Linehighhighs :=           line.new(bar_index, highhighs, bar_index, highhighs, color = color.white, width = 2)
    Linelowlows   :=           line.new(bar_index, lowlows, bar_index, lowlows, color = color.white, width = 2)
else
    line.set_x2(Linehighhighs, bar_index)
    line.set_x2(Linelowlows, bar_index)