Return elements of list as independent objects in global environment

问题

I have a list, and would like to break the elements of the list into seperate objects in the global environment.

For example, I would like the list:

obj <- list(a=1:5, b=2:10, c=-5:5)

to be three seperate objects a, b, and c.

I tried to achieve this with:

lapply(obj, FUN = function(x) names(x)[1] <<- x[1])

But it failed, with Error in names(x)[1] <<- x[1] : object 'x' not found.

How might I achieve my aim?

回答1:

There is special function for mapping list to environment:

> obj <- list(a=1:5, b=2:10, c=-5:5)
> ls()
[1] "obj"
> list2env(obj,globalenv())
<environment: R_GlobalEnv>
> ls()
[1] "a"   "b"   "c"   "obj"

P. S. It is my comment provided as an answer

回答2:

This also would work:

lapply(seq_along(obj), function(i) assign(names(obj)[i], obj[[i]], envir = .GlobalEnv))

回答3:

I don't recommend it but you could use attach

> obj <- list(a=1:5, b=2:10, c=-5:5)
> attach(obj)
> a
[1] 1 2 3 4 5
> b
[1]  2  3  4  5  6  7  8  9 10
> c
 [1] -5 -4 -3 -2 -1  0  1  2  3  4  5

来源：https://stackoverflow.com/questions/13795526/return-elements-of-list-as-independent-objects-in-global-environment