It's per design: ?names ... The name '""' is special: it is used to indicate that there is no name associated with an element of a (atomic or generic) vector. Subscripting by '""' will match nothing (not even elements which have no name). ...
Best, Serguei. Le 2023-09-11 18:29, Trevor Davis a écrit : > Hi, > > I notice that one can assign a variable to an R list by using an empty > string key but one cannot get that variable back from the list by using the > empty string key: > > ```r > l <- list() > l[[""]] <- "An empty string as list key" > names(l) > l[[""]] # Returns a `NULL` > l[[names(l) == ""]] # Returns first value with `""` tag > ``` > > Instead of `l[[""]]` returning a `NULL` I'd "expect" it to instead return > the first variable named `""` i.e. in this case "An empty string as list > key". It would be nice if the `[[` method of a list was updated to "fix" > this. > > Additionally, I observe that if a list is named but has certain elements > without names then those are currently "named" `""`: > > ```r > names(list(a = 1, 2, c = 3, 4)) > ``` > > This latter change may be a breaking change but I speculate that perhaps it > may be more intuitive if missing names were indicated with `NA_character_` > instead of `""`. > > Thanks, > > Trevor > > [[alternative HTML version deleted]] > > ______________________________________________ > R-devel@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel [[alternative HTML version deleted]] ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
