Function returning multiple values in R

Question

Say I have a function

f <- function(){

  # do things

  return(list(zoo = x, vector = y, integer = z))
}

When I call this function using

result <- f()

Is there any way to call the return variables explicitly? Ie do I have to call it using

vara <- result$vara
varb <- result$varb
varc <- result$varc

Since if this function returns a lot of data types (whether it be data frames, zoo's, vectors, etc). The reason I dont want to bind into data frame is because not all variables are of the same length.

Can you be a little more precise so you don't want to use result$vara and result["vara"] then what type you want — The6thSense
– The6thSense, Commented May 19, 2015 at 5:42
Like in some languages you can just do [x,y,z] = f(). Its clean and doesnt take up many lines. When I have to define the variables as above, its always written as result$<blah> — bob
– bob, Commented May 19, 2015 at 5:52
Yeah, I like that syntax too, but I think it's not available in R. The ugly workaround is attach(setNames(f(),c("a","b"))) — Frank
– Frank, Commented May 19, 2015 at 5:54

Richie Cotton · Accepted Answer · 2015-05-19 06:02:31Z

Use `with` or `within`

If the problem is just that you don't like typing result, then you can use with or within to access elements inside the list.

with(result, vara + varb * varc)

This is a good, standard way of doing things.

Use `list2env`

You could copy the variables from the list using list2env.

 list2env(result, parent.frame())

This is slightly risky because you have two copies of your variables which may introduce bugs. If you are including the code in a package, R CMD check will give you warnings about global variables.

Use `attach`

This is a really bad idea (don't do this).

attach is like a permanent version of with. If you

attach(result)

then you can access each element without the result$ prefix. But it will lead to many horrendous, obscure bugs in your code when an error gets thrown before you detach it, and then you attach it a second time and drown in a variable-scope-swamp.

Collectives™ on Stack Overflow

Function returning multiple values in R

1 Answer 1

Use `with` or `within`

Use `list2env`

Use `attach`

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Use with or within

Use list2env

Use attach

Comments

Your Answer

Sign up or log in

Post as a guest

Related

Use `with` or `within`

Use `list2env`

Use `attach`