Edit: I rewrite this question, as I have two related questions that maybe could be answered better together...
I've got some large nested lists with nearly the same structure and without names. All items of the list have attributes and I want to assign these as names in all levels of the list. Furthermore I want to drop a needless list-level.
So this:
before <- list(list("value_1"), list(list("value_2a"), list("value_2b")), list(list("value_3a"), list("value_3b"), list("value_3c")), list("value_4"))
for(i in 1:4) attr(before[[i]], "tag") <- paste0("tag_", i)
attr(before[[2]][[1]], "code") <- "code_2a"
attr(before[[2]][[2]], "code") <- "code_2b"
attr(before[[3]][[1]], "code") <- "code_3a"
attr(before[[3]][[2]], "code") <- "code_3b"
attr(before[[3]][[3]], "code") <- "code_3c"
str(before)
## List of 4
## $ :List of 1
## ..$ : chr "value_1"
## ..- attr(*, "tag")= chr "tag_1"
## $ :List of 2
## ..$ :List of 1
## .. ..$ : chr "value_2a"
## .. ..- attr(*, "code")= chr "code_2a"
## ..$ :List of 1
## .. ..$ : chr "value_2b"
## .. ..- attr(*, "code")= chr "code_2b"
## ..- attr(*, "tag")= chr "tag_2"
## $ :List of 3
## ..$ :List of 1
## .. ..$ : chr "value_3a"
## .. ..- attr(*, "code")= chr "code_3a"
## ..$ :List of 1
## .. ..$ : chr "value_3b"
## .. ..- attr(*, "code")= chr "code_3b"
## ..$ :List of 1
## .. ..$ : chr "value_3c"
## .. ..- attr(*, "code")= chr "code_3c"
## ..- attr(*, "tag")= chr "tag_3"
## $ :List of 1
## ..$ : chr "value_4"
## ..- attr(*, "tag")= chr "tag_4"
(Note: 1st level list items have a "tag"-attribute, 2nd level items have a "code"-attribute.)
Should be this:
after <- list(tag_1="value_1", tag_2=list(code_2a="value_2a", code_2b="value_2b"), tag_3=list(code_3a="value_3a", code_3b="value_3b", code_3c="value_3c"), tag_4="value_4")
str(after)
## List of 4
## $ tag_1: chr "value_1"
## $ tag_2:List of 2
## ..$ code_2a: chr "value_2a"
## ..$ code_2b: chr "value_2b"
## $ tag_3:List of 3
## ..$ code_3a: chr "value_3a"
## ..$ code_3b: chr "value_3b"
## ..$ code_3c: chr "value_3c"
## $ tag_4: chr "value_4"
Since the lists are large, I want to avoid for loops, to get a better performance.