Is there a elegant way to name the elements of a list according to the variables it has been composed of?

Question

I'm looking for a function that does the same as list, but puts the names of the input variables into the element names of the list:

a <- 2
b <- c("foo","bar")
betterlist(a,b)

[[a]]
[1] 2

[[b]]
[1] "foo" "bar"

In the output of list(a,b), the names "a" and "b" would not appear. Does it already exist in any package?

I don't know if this any better, but you could do `mget(ls(pattern = "[a-z]"))` or if you don't have any other objects in your environment, could do just `mget(ls())` — David Arenburg, Apr 15 '15 at 13:07
@Ben Bolker: I agree, it's a duplicate. I might have missed it. — Horst Grünbusch, Apr 15 '15 at 16:05

score 1 · Accepted Answer · answered Apr 15 '15 at 14:59

Here's one way using ... :

betterlist = function(...) {
  result <- list(...)
  resultnames <- lapply(substitute(list(...)), deparse)
  names(result) <- resultnames[-1]
  return(result)
}

This should actually be even easier as the R help states

The expression list(...) evaluates all such arguments and returns them in a named list [...]

but for me, list(...) gives me an unnamed list (hence the explicit naming in the function above).

score 0 · Answer 2 · answered Apr 15 '15 at 13:20

0

First guess:

list(a = a, b = b)

answered Apr 15 '15 at 13:20

Edward R. Mazurek

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Is there a elegant way to name the elements of a list according to the variables it has been composed of?

2 Answers2