Alternatives to using the request.security function within a For loop-CodePudding

I've written some code to determine the relative strength and weakness of the FTSE relative to the DAX and the CAC.

//Define the lookback period

lookback=10

//Determine if there is strength in the FTSE relative to the DAX and the CAC over the specified lookback period

relativestrengthindicator=0
relativeweaknessindicator=0
float FTSEreturn=0
float DAXreturn=0
float CACreturn=0
float relativereturntoDAX=0
float relativereturntoCAC=0


for i=0 to (lookback-1)

    FTSElastclose=request.security("UK100","5",close[i 1])
    FTSEsecondlastclose=request.security("UK100","5",close[i 2])

    FTSEreturn:=((FTSElastclose-FTSEsecondlastclose)/FTSEsecondlastclose)*100
    
    DAXlastclose=request.security("DE40","5",close[i 1])
    DAXsecondlastclose=request.security("DE40","5",close[i 2])

    DAXreturn:=((DAXlastclose-DAXsecondlastclose)/DAXsecondlastclose)*100

    CAClastclose=request.security("FR40","5",close[i 1])
    CACsecondlastclose=request.security("FR40","5",close[i 2])

    CACreturn:=((CAClastclose-CACsecondlastclose)/CACsecondlastclose)*100
    
    relativereturntoDAX:=FTSEreturn-DAXreturn
    relativereturntoCAC:=FTSEreturn-CACreturn
    
    if relativereturntoDAX>0 and relativereturntoCAC>0
        relativestrengthindicator:=relativestrengthindicator 1
        
    else if relativereturntoDAX<0 and relativereturntoCAC<0
        relativeweaknessindicator:=relativeweaknessindicator 1
        


plot(relativestrengthindicator)
plot(relativeweaknessindicator)

However, the error message produced is "Cannot call 'request.*()' function inside 'if', 'switch' or 'for'".

If I am unable to use the request.security function inside a For loop, how should I go about extracting the prices and including it in the For loop?

Thank you.

CodePudding user response：

You cannot do this as security needs to be constant and known at runtime as it creates a parallel chart to the current one.

CodePudding user response：

As mentioned, the request.security() function creates a parallel chart to the current one. You can solve your issue by creating this parallel chart, and then call it inside the for loop. The code will look like this:

//@version=5
strategy("My strategy", overlay=true, margin_long=100, margin_short=100)
lookback=10

//Determine if there is strength in the FTSE relative to the DAX and the CAC over the specified lookback period

relativestrengthindicator=0
relativeweaknessindicator=0
float FTSEreturn=0
float DAXreturn=0
float CACreturn=0
float relativereturntoDAX=0
float relativereturntoCAC=0

FTSEclose = request.security("UK100","5",close)
DAXclose = request.security("DE40","5",close)
CACclose = request.security("FR40","5",close)

for i=0 to (lookback-1)

    FTSElastclose = FTSEclose[i 1]
    FTSEsecondlastclose = FTSEclose[i 2]

    FTSEreturn:=((FTSElastclose-FTSEsecondlastclose)/FTSEsecondlastclose)*100
    
    DAXlastclose = DAXclose[i 1]
    DAXsecondlastclose = DAXclose[i 2]

    DAXreturn:=((DAXlastclose-DAXsecondlastclose)/DAXsecondlastclose)*100

    CAClastclose = CACclose[i 1]
    CACsecondlastclose = CACclose[i 2]

    CACreturn:=((CAClastclose-CACsecondlastclose)/CACsecondlastclose)*100
    
    relativereturntoDAX:=FTSEreturn-DAXreturn
    relativereturntoCAC:=FTSEreturn-CACreturn
    
    if relativereturntoDAX>0 and relativereturntoCAC>0
        relativestrengthindicator:=relativestrengthindicator 1
        
    else if relativereturntoDAX<0 and relativereturntoCAC<0
        relativeweaknessindicator:=relativeweaknessindicator 1
        


plot(relativestrengthindicator)
plot(relativeweaknessindicator)