Copy a data frame in a function - r

Question

I want to copy data frame a to a new data frame b inside a function.
a <- mtcars
saveData <- function(x, y){
y <- x
return(y)
}
saveData(a, b)
In this example, the function should create the object/data frame b. b should be a copy of a (i.e., mtcars)
The crux is to flexibly "name" objects.
I excessively played around with assign(), deparse(), and substitute(), but I could not make it work.

Answer 1

It is not a good pracrtice to save the data in global environment from a function. However if you want to do it here is a way :
saveData <- function(x, y){
assign(deparse(substitute(y)), x, envir = parent.frame())
}
a <- mtcars
b
Error: object 'b' not found
saveData(a, b)
b
# mpg cyl disp hp drat wt qsec vs am gear carb
#Mazda RX4 21.0 6 160.0 110 3.90 2.620 16.46 0 1 4 4
#Mazda RX4 Wag 21.0 6 160.0 110 3.90 2.875 17.02 0 1 4 4
#Datsun 710 22.8 4 108.0 93 3.85 2.320 18.61 1 1 4 1
#Hornet 4 Drive 21.4 6 258.0 110 3.08 3.215 19.44 1 0 3 1
#Hornet Sportabout 18.7 8 360.0 175 3.15 3.440 17.02 0 0 3 2
#...

Answer 2

Another idea is to use list2env, but you have to convert to a named list, so your second argument will need to be a character, i.e.
saveData <- function(x, y) {
v1 <- setNames(list(x), y)
list2env(v1, envir = .GlobalEnv)
}
saveData(a, 'b')
b
# mpg cyl disp hp drat wt qsec vs am gear carb
#Mazda RX4 21.0 6 160.0 110 3.90 2.620 16.46 0 1 4 4
#Mazda RX4 Wag 21.0 6 160.0 110 3.90 2.875 17.02 0 1 4 4
#Datsun 710 22.8 4 108.0 93 3.85 2.320 18.61 1 1 4 1
#Hornet 4 Drive 21.4 6 258.0 110 3.08 3.215 19.44 1 0 3 1
#Hornet Sportabout 18.7 8 360.0 175 3.15 3.440 17.02 0 0 3 2
#.....
NOTE: I wouldn't recommend adding staff to your global environment. It is better to keep them in lists