[R] I need to create new variables based on two numeric variables and one dichotomize conditional category variables.

[CALUM POLWART]

I might have factored the gender.

I'm not sure it would in any way be quicker.  But might be to some extent
easier to develop variations of. And is sort of what factors should be
doing...

# make dummy data
gender <- c("Male", "Female", "Male", "Female")
WC <- c(70,60,75,65)
TG <- c(0.9, 1.1, 1.2, 1.0)
myDf <- data.frame( gender, WC, TG )

# label a factor
myDf$GF <- factor(myDf$gender, labels= c("Male"=65, "Female"=58))

# do the maths
myDf$LAP <- (myDf$WC - as.numeric(myDf$GF))* myDf$TG

#show results
head(myDf)

gender WC  TG GF  LAP
1   Male 70 0.9 58 61.2
2 Female 60 1.1 65 64.9
3   Male 75 1.2 58 87.6
4 Female 65 1.0 65 64.0


(Reality: I'd have probably used case_when in tidy to create a new numeric
column)





The equation to
> calculate LAP is different for male and females. I am giving both equations
> below.
>
> LAP for male = (WC-65)*TG
> LAP for female = (WC-58)*TG
>
> My question is 'how can I calculate the LAP and create a single new column?
>
>

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