Getting name of an object from list in Map - r

Question

Given the following data:
list_A <- list(data_cars = mtcars,
data_air = AirPassengers,
data_list = list(A = 1,
B = 2))
I would like to print names of objects available across list_A.
Example:
Map(
f = function(x) {
nm <- deparse(match.call()$x)
print(nm)
# nm object is only needed to properly name flat file that may be
# produced within Map call
if (any(class(x) == "list")) {
length(x) + 1
} else {
length(x) + 1e6
saveRDS(object = x,
file = tempfile(pattern = make.names(nm), fileext = ".RDS"))
}
},
list_A
)
returns:
[1] "dots[[1L]][[1L]]"
[1] "dots[[1L]][[2L]]"
[1] "dots[[1L]][[3L]]"
$data_cars
NULL
$data_air
NULL
$data_list
[1] 3
Desired results
I would like to get:
`data_cars`
`data_air`
`data_list`
Update
Following the comments, I have modified the example to make it more reflective of my actual needs which are:
While using Map to iterate over list_A I'm performing some operations on each element of the list
Periodically I want to create a flat file with name reflecting name of object that was processed
In addition to list_A, there are also list_B, list_C and so forth. Therefore, I would like to avoid calling names(list) inside the function f of the Map as I will have to modify it n number of times. The solution I'm looking to find should lend itself for:
Map(function(l){...}, list_A)
So I can later replace list_A. It does not have to rely on Map. Any of the apply functions would do; same applied to purrr-based solutions.
Alternative example
do_stuff <- function(x) {
nm <- deparse(match.call()$x)
print(nm)
# nm object is only needed to properly name flat file that may be
# produced within Map call
if (any(class(x) == "list")) {
length(x) + 1
} else {
length(x) + 1e6
saveRDS(object = x,
file = tempfile(pattern = make.names(nm), fileext = ".RDS"))
}
}
Map(do_stuff, list_A)
As per the notes below, I want to avoid having to modify do_stuff function as I will be looking to do:
Map(do_stuff, list_A)
Map(do_stuff, list_B)
Map(do_stuff, list_...)

Answer 1

We could wrap it into a function, and do it in two steps:
myFun <- function(myList){
# do stuff
res <- Map(
f = function(x) {
#do stuff
head(x)
},
myList)
# write to a file, here we might add control
# if list is empty do not output to a file
for(i in names(res)){
write.table(res[[ i ]], file = paste0(i, ".txt"))
}
}
myFun(list_A)

Answer 2

Would something like this work ?
list_A2 <- Map(list, x = list_A,nm = names(list_A) )
trace(do_stuff, quote({ nm <- x$nm; x<- x$x}), at=3)
Map(do_stuff, list_A2)