[Rd] mapply(): Special case of USE.NAMES=TRUE with recent R-devel updates

Henrik Bengtsson henr|k@bengt@@on @end|ng |rom gm@||@com
Wed Dec 1 07:10:34 CET 2021


in R-devel (4.2.0), we now get:

> mapply(paste, "A", character(), USE.NAMES = TRUE)
named list()

Now, in ?mapply we have:

USE.NAMES: logical; use the names of the first ... argument, or if
that is an unnamed character vector, use that vector as the names.

This basically says we should get:

> answer <- list()
> first <- "A"
> names(answer) <- first

which obviously is an error. The help is not explicit what should
happen when the length "of the first ... argument" is zero, but the
above behavior effectively does something like:

> answer <- list()
> first <- "A"
> names(answer) <- first[seq_along(answer)]
> answer
named list()

Is there a need for the docs to be updated, or should the result be an
unnamed empty list?


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