Automatically Named list()

A version of list(...), but with “automatically” named list components.

list_(...)

Details

The names are extracted from sys.call(), and the function is written to be fast (rather than easy to ready for the uninitiated ;-)

Arguments

...

components to make up the resulting list. Their variable names (or unevaluated expressions in the call) will become the names(.) of the result.

Value

a list with the components in the arguments with names taken from their call to list_(..).

Author

Martin Maechler

See also

list, names

Examples

a <- 1:4; lett <- letters[1:9]; CH <- "Suisse"
all.equal(list (a, lett),
          list_(a, lett)) # "names for current but not for target"
#> [1] "names for current but not for target"
str(list(a, lett, CH)) # [[1]], [[2]], .. (no names)
#> List of 3
#>  $ : int [1:4] 1 2 3 4
#>  $ : chr [1:9] "a" "b" "c" "d" ...
#>  $ : chr "Suisse"
str(list_(a, lett, CH))#   $a   $lett  ..
#> List of 3
#>  $ a   : int [1:4] 1 2 3 4
#>  $ lett: chr [1:9] "a" "b" "c" "d" ...
#>  $ CH  : chr "Suisse"

stopifnot(identical(            list (a, lett, CH),
                    unname(L <- list_(a, lett, CH))),
          is.list(L), names(L) == c("a", "lett", "CH"),
          identical(lett, L$lett) ## etc
          )

## The function is currently defined as
function (...) `names<-`(list(...), vapply(sys.call()[-1L], as.character, ""))
#> function (...) 
#> `names<-`(list(...), vapply(sys.call()[-1L], as.character, ""))
#> <environment: 0x55dd15703ef0>