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rinputvariable-names

Input variable name handling in R

I would like to learn about how to handle an input of a variable name in a function. For example, I have written a function like this:

bin_multi <- function(y, dataframe, sel = NULL){
  if(!is.null(sel)) {
     dataframe <- dataframe[,sel]}
  else {
     dataframe <- dataframe[!y]}
}

Where dataframe is the input dataframe, y is the target variable in the dataframe, sel is the selection of columns from dataframe, for example, sel = c(1,2,3).

The purpose of this function is to simply take a subset of dataframe with a given sel, and when sel is not given, exclude y the target variable from the dataframe.

My question is, how could I refer properly to y in this function? In the input, y is the name of a variable. Could deparse() solve this problem?

Thank you all.

Solution

  • I think this will work:

    bin_multi <- function(y, dataframe, sel = NULL){

  if(!is.null(sel)) {

     dataframe <- dataframe[,sel]

  } else {

     dataframe <- dataframe[,which(names(dataframe) != deparse(substitute(y)))]

  }

}

    That's drawing on this answer to turn your object name into a string.