How work 'for' in Pine language (TradingView) and how call MACD in loop?

Question

Please teach me how to use the for loop in the Pine language (scripts for TradingView charts). I made a test indicator (code below), which displays the MACD. In green chart, I simply display MACD at the top level of the script. I get the same MACD value in red chart, but taken inside the 'for' loop. See how it works:

the loop increments the value of n from 0 to 20
when n is 0, the script takes the MACD value and writes it to the cell val
then there are another 20 empty steps.
at the end, the script displays val on the screen, completing the red chart

Logically, the green and red graphics should ideally match, since they display the same values. But they are different !!! Help understand the error. Thank you.

//@version=4
study("My Script")

[_,_,currMacd] = macd(close[0], 12, 26, 9)
plot(currMacd, style=plot.style_histogram, color=color.green)

//
float val = 0.0
for int n = 0 to 20
    [_,_,tempMacd] = macd(close[n], 12, 26, 9)
    if n == 0
        val := tempMacd

plot(val, style=plot.style_histogram, color=color.red)

Screenshot of TradingView

PineCoders-LucF PineCoders-LucF · Accepted Answer · 2020-04-16T10:08:56

Not too sure what you're trying to accomplish here, but your MACD is already calculated on past bars, so you only need to refer to past values:

//@version=4
study("My Script")

[_,_,currMacd] = macd(close, 12, 26, 9)
plot(currMacd, style=plot.style_histogram, color=color.orange, linewidth = 8, transp = 60)

float val = 0.0
for int n = 0 to 20
    val := currMacd[n]
    if n == 0
        break

plot(val, style=plot.style_histogram, color=color.red)

How work 'for' in Pine language (TradingView) and how call MACD in loop?

1 Answers