CODEWITHSUNDEEP
r
Rover Eye
Rover Eye

Reputation: 237

Passing argument to factor() in R

I have a R code that looks something like this:

StatFunction <- function(CSVImport, AnimalID_i,Treatment_i){

  #Data Input from a CSV file (example below)
  Data <- read.csv(CSVImport)

All goes well so far, as the data is read off the csv file. I am calling the function like this

StatFunction (path/to/file/, "Animal", "Treatment")

Note that the input arguments are strings representing the column name of the CSV. Now, I try to sort out the data frame like this:

  #Trying to sort out the input
  Data <- within(Data, {

    FinalID <-  (factor(as.character(FinalID_i))) 
    AnimalID <- (factor(as.character(AnimalID_i)))

This doesn't work with the argument of the StatFunction. It gives me this

[1] "---Final ID---"
[1] Treatment
Levels: Treatment
[1] "---Animal ID---"
[1] Animal
Levels: Animal

When, Substituting the arguments directly into the code, like this

    FinalID <-  (factor(Treatment))                
    AnimalID <- (factor(Animal))

It gives me the expected result.

    [1] "---Final ID---"
    [1] 0 0 1 1 1
    Levels: 0 1
    [1] "---Animal ID---"
    [1] 722 723 724 727 728
    Levels: 722 723 724 727 728

So my question is how to make this work when passing arguments and not burning the names in the code?

Upvotes: 0

Views: 800

Answers (2)

Rich Scriven
Rich Scriven

Reputation: 99331

Why not go back a step and add the fact that you want factor columns via their names by adding a colClasses argument that is passed to read.csv(). Or you can just add , ...) and do the same thing. The ... can be sent to the read.csv() argument list.

statFunction <- function(file, colClasses = character(), ...) {
    read.csv(file, colClasses = colClasses, ...)
}

And call statFunction() like this

statFunction(
    file, 
    colClasses = c(Animal = "factor", Treatment = "factor")
)

Upvotes: 0

MrFlick
MrFlick

Reputation: 206197

You can't just swap character and symbol values. If you want to extract data with a character value, then use

Data$FinalID <- factor(as.character(Data[[FinalID_i]]))
Data$AnimalID  <- factor(as.character(Data[[AnimalID_i]]))

Upvotes: 1

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