CODEWITHSUNDEEP
rfunctionloops
LostSamurai
LostSamurai

Reputation: 63

Is there a way to simplify functions in R that utilize loops?

For example, I’m currently working on a function that allows you to see how much money you might have if you invested in the stock market. It’s currently using a loop structure, which is really irritating me, because I know there probably is a better way to code this and leverage vectors in R. I’m also creating dummy vectors before running the function, which seems a bit strange too.

Still a beginner at R (just started!), so any helpful guidance is highly appreciated!

set.seed(123)
##Initial Assumptions 
initialinvestment <- 50000 # e.g., your starting investment is $50,000
monthlycontribution <- 3000 # e.g., every month you invest $3000 
months <- 200 # e.g., how much you get after 200 months

##Vectors
grossreturns <- 1 + rnorm(200, .05, .15) # approximation of gross stock market returns
contribution <- rep(monthlycontribution, months)
wealth <- rep(initialinvestment, months + 1)

##Function
projectedwealth <- function(wealth, grossreturns, contribution) {
  for(i in 2:length(wealth))
    wealth[i] <- wealth[i-1] * grossreturns[i-1] + contribution[i-1]
  wealth
}

##Plot
plot(projectedwealth(wealth, grossreturns, contribution))

Upvotes: 6

Views: 127

Answers (1)

A. Webb
A. Webb

Reputation: 26446

I would probably write

Reduce(function(w,i) w * grossreturns[i]+contribution[i],
  1:months,initialinvestment,accum=TRUE)

but that's my preference for using functionals. There is nothing wrong with your use of a for loop here.

Upvotes: 10

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