How can I pass multiple arguments to a function as a single vector?

Question

I created the following function with six args:

nDone <- function(under,strike,ttoe,vol,rf,dy) {     pnorm(((log(under/strike)+ (rf-dy+(vol^2)/2)*ttoe)/(vol*(ttoe^0.5)))) }  nDone(90,100,3,0.17,0.05,0) # Result:  [1] 0.6174643 

Now I create a vector with the same values in an object, and try to call the function using the vector, but get the following error:

d <- c(90,100,3,0.17,0.05,0)  nDone(d)  Error in under/strike : 'strike' is missing 

What am I doing wrong and how to fix?

Answer 1

Try this

 do.call(nDone, as.list(d)) 

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Explanation of what's happening in your first attempt by @joran from the comments:

R is seeing you pass a single argument to nDone, namely the vector d, which is handed off to the first function argument, under. Since you haven't specified a default value for the others, they are missing and hence the error

Answer 2

Maybe worth to add:

If your function can accept arguments that are vectors of length >1 and generates output of the same length, do.call can handle that, too, and you will need list():

x <- c("a", "b", "c") y <- c(1, 2, 3)  > do.call(paste0,c(list(x),list(y))) [1] "a1" "b2" "c3" 

watch out that this won't fail or warn for vectors of unequal lengths:

x <- c("a", "b")  > do.call(paste0,c(list(x),list(y))) [1] "a1" "b2" "a3" 

Of course paste0(x,y) would work here just as well, but I'm using this e.g. for rgb():

# whichever complex functions to generate vector of floats: x <- seq(1,6) %>% exp()  # rescale for rgb x <- scales::rescale(x)  # make a list of vectors # note that as.list() would not give the desired output here x <- rep(list(x),3)  # call > do.call(rgb, x) [1] "#000000" "#030303" "#0B0B0B" "#212121" "#5D5D5D" "#FFFFFF" 

or a tidy one line:

> seq(1,6) %>% exp() %>% scales::rescale() %>% list() %>% rep(3) %>% do.call(rgb,.) [1] "#000000" "#030303" "#0B0B0B" "#212121" "#5D5D5D" "#FFFFFF"