[R] Passing variable names in quotes to a function

[phgrosjean at sciviews.org]

Your example and explanation are not complete, but I have the gut feeling that you could do all this both more efficiently *and* more R-ish.

First of all, why would you pass Y and X separately, to ultimately build the Y ~ X formula within the body of your function?

Secondly, it seems to me that subY and subY.val does something very similar to the subset argument in, say, lm().

Personally, I would write it like this:

foo <- function(formula, data, subset) {
  if (!missing(subset))
    data <- data[subset, ]
  fit <- some_regression_tool(formula, data = data)

  ## <more code>

  data_after_processing
}
 
with subset = subY == subY.val.

Best,

Philippe

> On 02 Dec 2015, at 06:11, Brant Inman <brant.inman at me.com> wrote:
> 
> I am trying to build a function that can accept variables for a regression.  It would work something like this:
> 
> ---
> # Y = my response variable (e.g. income)
> # X = my key predictor variable (e.g. education)
> # subY = a subsetting variable for Y (e.g. race)
> # subY.val = the value of the subsetting value that I want (e.g. ‘black’)
> 
> foo <- function(Y, X, subY, subY.val, dataset){
> 
>  if(is.na(subY) == F) {
>     Y <- paste(Y, ‘[‘, subY, ‘==‘, subY.val, ‘]’)
>  }
>  FORMULA <- paste(Y ~ X)
>  fit <- some.regression.tool(FORMULA, data=dataset)
> 
>  return(some.data.after.processing)
> }
> ---
> 
> If I call this function with, foo(income, education, race, “black”, my.dataset), I do not get the result that I need because the FORMULA is "income[race==black] ~ education” when what I need is “income[race==‘black’] ~ education”.  How do I get the quotes to stay on ‘black’?  Or, is there a better way?
> 
> Help appreciated.
> 
> --
> Brant
> 	[[alternative HTML version deleted]]
> 
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