Change a dynamic variable name with rxSetVarInfo - microsoft-r

Question

Trying to change a variable name of an XDF with rxSetVarInfo.
I want to merge several data sets with common var names. (I know rxMerge can/will append to filenames where needed. I want to have more control than that.)
This works:
outLetter<- "A"
exp <- list(pct.A = list(newName = paste0("X.pct.",outLetter)))
rxSetVarInfo(varInfo = exp, data = tempXDFFile)
That's where I know the original column name, pct.A. What if that's dynamic? What if this is in a function that gets called several times with different outLetter's. (The "A" isn't hardcoded.)
This does not work:
function(outLetter){
exp <- list(paste0("pct.",outLetter) = list(newName = paste0("X.pct.",outLetter)))
rxSetVarInfo(varInfo = exp, data = tempXDFFile)
}
Nor does:
exp <- parse(text = exp)
rxSetVarInfo(varInfo = exp, data = tempXDFFile)
Yes, I can hardcode all the permutations. Trying to find a more elegant approach.

Answer 1

Please try this code:
dynamicName <- function(outLetter){
exp <- vector(mode="list", length=1)
names(exp) <- paste0("pct.",outLetter)
exp[[paste0("pct.",outLetter)]] = list(newName = paste0("X.pct.",outLetter))
rxSetVarInfo(varInfo = exp, data = tempXDFFile)
}
Before the call to rxSetVarInfo(), "exp" contains:
$pct.A
$pct.A$newName
[1] "X.pct.A"
Running your "this works" case, I see:
> outLetter<- "A"
> exp <- list(pct.A = list(newName = paste0("X.pct.",outLetter)))
>
> exp
$pct.A
$pct.A$newName
[1] "X.pct.A"
Hope this helps!
Note, please make sure that your dynamic naming function has access to the variable "tempXDFFile", you may want to consider passing it as a parameter, like:
dynamicName <- function(outLetter, data){
exp <- vector(mode="list", length=1)
names(exp) <- paste0("pct.",outLetter)
exp[[paste0("pct.",outLetter)]] = list(newName = paste0("X.pct.",outLetter))
rxSetVarInfo(varInfo = exp, data = data)
}