Arguments to a function in R

Question

I'm a beginner and I'm trying to write a function that fits a model (univariate) one variable at a time. I want to able to enter all the dependent variables when calling the function and then make the function to fit one variable at a time. Something like:

f <-function(y, x1,x2,x3) {(as.formula(print()))...}

I tried to make a list of x1 , x2 , x3 inside the function but it didn't work.

Maybe someone here could help me with this or point me in the right direction.

Answer 1

Here's something that might get you going. You can put your x variables inside a list, and then fit once for each element inside the list.

fitVars <- function(y, xList) {
  lapply(xList, function(x) lm(y ~ x))
}

y <- 1:10
set.seed(10)
xVals <- list(rnorm(10), rnorm(10), rnorm(10))

fitVars(y, xVals)

This returns one fit result for each element of xVals:

[[1]]

Call:
lm(formula = y ~ x)

Coefficients:
(Intercept)            x  
      4.984       -1.051  


[[2]]

Call:
lm(formula = y ~ x)

Coefficients:
(Intercept)            x  
      5.986       -1.315  


[[3]]

Call:
lm(formula = y ~ x)

Coefficients:
(Intercept)            x  
      7.584        2.282  

Another option is to use the ... holder to use an arbitrary number of arguments:

fitVars <- function(y, ...) {
  xList <- list(...)
  lapply(xList, function(x) lm(y ~ x))
}

set.seed(10)
fitVars(y, rnorm(10), rnorm(10), rnorm(10))

This gives the same result as above.