[R] how to assign a value to a specific position of a list

[MacQueen, Don]

It's not clear what you're trying to do. However, to "assign a value to a specific position of a list", this example should show you how.

lst <- vector('list', 10)       ## see the help page for list
names(lst) <- paste0('list.',1:10)

## to assign 'a' to position 3:
pos <- 3
lst[[pos]] <- 'a'

I completely agree with Jeff Newmiller's recommendation to avoid using assign. It's probably the wrong tool for what you're trying to do (whatever that is).
(and note that I have borrowed Jeff's name "lst" for the list with 10 elements [not variables] whose names are "list_1" "list_2" etc.)
(and I refuse to use "_" in R object names, but that's a personal preference)

-Don

-- 
Don MacQueen

Lawrence Livermore National Laboratory
7000 East Ave., L-627
Livermore, CA 94550
925-423-1062


On 4/30/17, 8:17 AM, "R-help on behalf of Jinsong Zhao" <r-help-bounces at r-project.org on behalf of jszhao at yeah.net> wrote:

    Hi there,
    
    I have a problem with assign(). Here is the demo code:
    
    for (i in 1:10) {
        # create a list with variable name as list_1, list_2, ..., etc.
        assign(paste("list_", i, sep = ""), list())
        # I hope to assign 5 to list_?[[1]], but I don't know how to code it.
        # list_1[[1]] <- 5 # works, however
        assign(paste("list_", i, "[[1]]", sep = "", 5) # does not work
    }
    
    How to do? Is there any alternatives? Many thanks!
    
    Best,
    Jinsong
    
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