Call an argument name within a function in R

Question

I would like to create a generic function naTrans that replaces 'NA' and '' by NA.

The problem is that I can't replace the dataframe testin the global environment by the modified test dataframe (mydf) created within the function. Here's my best try.

# Example dataframe containing 'NA'
test <- as.data.frame(matrix(sample(c('NA', 1:9), 10*10, TRUE), 10))

# My function
naTrans <- function (mydf) {
  mydf[mydf == 'NA' | mydf ==''] <- NA
  assign(deparse(substitute(mydf))[1], mydf, envir = globalenv())
}

test <- naTrans(test)

any(is.na(test))
# [1] FALSE

Surely the problem lies in the last line of code assign(print(deparse(substitute(mydf))), mydf, envir = globalenv())

Any idea?

Answer 1

I hope the comments in the code are clear enough

test <- as.data.frame(matrix(sample(c('NA',1:9),10*10,T),10))

naTrans <- function (mydf) {
      mydf[mydf == 'NA' | mydf == ''] <- NA # use and or opertor, %in% don't work on DF but on vectors
      return(mydf) # return the modified mydf (the return is optionnal, you may just use mydf here 
}

test <- naTrans(test) # replace actual object by caller.