iteratively adding elements to list in one step

Question

I would like to add list elements iteratively in R, so that later elements can use the elements created earlier. The desired behavior is as follows:

lst <- list(a = 1, 
            b = 2, 
            c = b)
lst
## $a
## [1] 1
## 
## $b
## [1] 2
## 
## $c
## [1] 2

I know that I can easily accomplish the same using e.g.

lst <- list(a = 1, 
            b = 2)
lst[['c']] <- lst[['b']]

But I was wondering, if I could do this in one step.

Answer 1

Here's another way

rev(within(list(), { a = 1; b = 2; c = b }))
# $a
# [1] 1
# 
# $b
# [1] 2
# 
# $c
# [1] 2

Answer 2

Update: This is now possible with the lst function of the tibble package:

tibble::lst(a = 1, b = 2, c = b)
## $a
## [1] 1
## 
## $b
## [1] 2
## 
## $c
## [1] 2

My previous workaround was using mutate from plyr:

mylist <- function(...) plyr::mutate(.data=list(), ...)

mylist(a = 1, 
       b = 2, 
       c = b)
## $a
## [1] 1
## 
## $b
## [1] 2
## 
## $c
## [1] 2