Davis Vaughan
2023-May-01 12:46 UTC
[Rd] range() for Date and POSIXct could respect `finite = TRUE`
Martin, Yes, I missed that those have `Summary.*` methods, thanks! Tweaking those to respect `finite = TRUE` sounds great. It seems like it might be a little tricky since the Summary methods call `NextMethod()`, and `range.default()` uses `is.numeric()` to determine whether or not to apply `finite`. Because `is.numeric.Date()` is defined, that always returns `FALSE` for Dates (and POSIXt). Because of that, it may still be easier to just write a specific `range.Date()` method, but I'm not sure. -Davis On Sat, Apr 29, 2023 at 4:47?PM Martin Maechler <maechler at stat.math.ethz.ch> wrote:> > >>>>> Davis Vaughan via R-devel > >>>>> on Fri, 28 Apr 2023 11:12:27 -0400 writes: > > > Hi all, > > > I noticed that `range.default()` has a nice `finite > > TRUE` argument, but it doesn't actually apply to Date or > > POSIXct due to how `is.numeric()` works. > > Well, I think it would / should never apply: > > range() belongs to the "Summary" group generics (as min, max, ...) > > and there *are* Summary.Date() and Summary.POSIX{c,l}t() methods. > > Without checking further for now, I think you are indirectly > suggesting to enhance these three Summary.*() methods so they do > obey 'finite = TRUE' . > > I think I agree they should. > > Martin > > > ``` x <- .Date(c(0, Inf, 1, 2, Inf)) x #> [1] "1970-01-01" > > "Inf" "1970-01-02" "1970-01-03" "Inf" > > > # Darn! range(x, finite = TRUE) #> [1] "1970-01-01" "Inf" > > > # What I want .Date(range(unclass(x), finite = TRUE)) #> > > [1] "1970-01-01" "1970-01-03" ``` > > > I think `finite = TRUE` would be pretty nice for Dates in > > particular. > > > As a motivating example, sometimes you have ranges of > > dates represented by start/end pairs. It is fairly natural > > to represent an event that hasn't ended yet with an > > infinite date. If you need to then compute a sequence of > > dates spanning the full range of the start/end pairs, it > > would be nice to be able to use `range(finite = TRUE)` to > > do so: > > > ``` start <- as.Date(c("2019-01-05", "2019-01-10", > > "2019-01-11", "2019-01-14")) end <- > > as.Date(c("2019-01-07", NA, "2019-01-14", NA)) > > end[is.na(end)] <- Inf > > > # `end = Inf` means that the event hasn't "ended" yet > > data.frame(start, end) #> start end #> 1 2019-01-05 > > 2019-01-07 #> 2 2019-01-10 Inf #> 3 2019-01-11 2019-01-14 > > #> 4 2019-01-14 Inf > > > # Create a full sequence along all days in start/end range > > <- .Date(range(unclass(c(start, end)), finite = TRUE)) > > seq(range[1], range[2], by = 1) #> [1] "2019-01-05" > > "2019-01-06" "2019-01-07" "2019-01-08" "2019-01-09" #> [6] > > "2019-01-10" "2019-01-11" "2019-01-12" "2019-01-13" > > "2019-01-14" ``` > > > It seems like one option is to create a `range.Date()` > > method that unclasses, forwards the arguments on to a > > second call to `range()`, and then reclasses? > > > ``` range.Date <- function(x, ..., na.rm = FALSE, finite > > FALSE) { .Date(range(unclass(x), na.rm = na.rm, finite > > finite), oldClass(x)) } ``` > > > This is similar to how `rep.Date()` works. > > > Thanks, Davis Vaughan > > > ______________________________________________ > > R-devel at r-project.org mailing list > > https://stat.ethz.ch/mailman/listinfo/r-devel
Martin Maechler
2023-May-04 09:29 UTC
[Rd] range() for Date and POSIXct could respect `finite = TRUE`
>>>>> Davis Vaughan >>>>> on Mon, 1 May 2023 08:46:33 -0400 writes:> Martin, > Yes, I missed that those have `Summary.*` methods, thanks! > Tweaking those to respect `finite = TRUE` sounds great. It seems like > it might be a little tricky since the Summary methods call > `NextMethod()`, and `range.default()` uses `is.numeric()` to determine > whether or not to apply `finite`. Because `is.numeric.Date()` is > defined, that always returns `FALSE` for Dates (and POSIXt). Because > of that, it may still be easier to just write a specific > `range.Date()` method, but I'm not sure. > -Davis I've looked more closely now, and indeed, range() is the only function in the Summary group where (only) the default method has a 'finite' argument. which strikes me as somewhat asymmetric / inconsequential, as after all, range(.) := c(min(.), max(.)) , but min() and max() do not obey an finite=TRUE setting, note> min(c(-Inf,3:5), finite=TRUE)Error: attempt to use zero-length variable name where the error message also is not particularly friendly and of course has nothing to with 'finite' :> max(1:4, foo="bar")Error: attempt to use zero-length variable name>... but that is diverting; coming back to the topic: Given that 'finite' only applies to range() {and there is just a convenience}, I do agree that from my own work & support to make `Date` and `POSIX(c)t` behave more number-like, it would be "nice" to have range() obey a `finite=TRUE` also for these. OTOH, there are quite a few other 'number-like' thingies for which I would then like to have range(*, finite=TRUE) work, e.g., "mpfr" (package {Rmpfr}) or "bigz" {gmp} numbers, numeric sparse matrices, ... To keep such methods all internally consistent with range.default(), I could envision something like this .rangeNum <- function(..., na.rm = FALSE, finite = FALSE, isNumeric) { x <- c(..., recursive = TRUE) if(isNumeric(x)) { if(finite) x <- x[is.finite(x)] else if(na.rm) x <- x[!is.na(x)] c(min(x), max(x)) } else { if(finite) na.rm <- TRUE c(min(x, na.rm=na.rm), max(x, na.rm=na.rm)) } } range.default <- function(..., na.rm = FALSE, finite = FALSE) .rangeNum(..., na.rm=na.rm, finite=finite, isNumeric = is.numeric) range.POSIXct <- range.Date <- function(..., na.rm = FALSE, finite = FALSE) .rangeNum(..., na.rm=na.rm, finite=finite, isNumeric = function(.)TRUE) which would also provide .rangeNum() to be used by implementors of other numeric-like classes to provide their own range() method as a 1-liner *and* be future-consistent with the default method.. > On Sat, Apr 29, 2023 at 4:47?PM Martin Maechler > <maechler at stat.math.ethz.ch> wrote: >> >> >>>>> Davis Vaughan via R-devel >> >>>>> on Fri, 28 Apr 2023 11:12:27 -0400 writes: >> >> > Hi all, >> >> > I noticed that `range.default()` has a nice `finite >> > TRUE` argument, but it doesn't actually apply to Date or >> > POSIXct due to how `is.numeric()` works. >> >> Well, I think it would / should never apply: >> >> range() belongs to the "Summary" group generics (as min, max, ...) >> >> and there *are* Summary.Date() and Summary.POSIX{c,l}t() methods. >> >> Without checking further for now, I think you are indirectly >> suggesting to enhance these three Summary.*() methods so they do >> obey 'finite = TRUE' . >> >> I think I agree they should. >> >> Martin >> >> > ``` x <- .Date(c(0, Inf, 1, 2, Inf)) x #> [1] "1970-01-01" >> > "Inf" "1970-01-02" "1970-01-03" "Inf" >> >> > # Darn! range(x, finite = TRUE) #> [1] "1970-01-01" "Inf" >> >> > # What I want .Date(range(unclass(x), finite = TRUE)) #> >> > [1] "1970-01-01" "1970-01-03" ``` >> >> > I think `finite = TRUE` would be pretty nice for Dates in >> > particular. >> >> > As a motivating example, sometimes you have ranges of >> > dates represented by start/end pairs. It is fairly natural >> > to represent an event that hasn't ended yet with an >> > infinite date. If you need to then compute a sequence of >> > dates spanning the full range of the start/end pairs, it >> > would be nice to be able to use `range(finite = TRUE)` to >> > do so: >> >> > ``` start <- as.Date(c("2019-01-05", "2019-01-10", >> > "2019-01-11", "2019-01-14")) end <- >> > as.Date(c("2019-01-07", NA, "2019-01-14", NA)) >> > end[is.na(end)] <- Inf >> >> > # `end = Inf` means that the event hasn't "ended" yet >> > data.frame(start, end) #> start end #> 1 2019-01-05 >> > 2019-01-07 #> 2 2019-01-10 Inf #> 3 2019-01-11 2019-01-14 >> > #> 4 2019-01-14 Inf >> >> > # Create a full sequence along all days in start/end range >> > <- .Date(range(unclass(c(start, end)), finite = TRUE)) >> > seq(range[1], range[2], by = 1) #> [1] "2019-01-05" >> > "2019-01-06" "2019-01-07" "2019-01-08" "2019-01-09" #> [6] >> > "2019-01-10" "2019-01-11" "2019-01-12" "2019-01-13" >> > "2019-01-14" ``` >> >> > It seems like one option is to create a `range.Date()` >> > method that unclasses, forwards the arguments on to a >> > second call to `range()`, and then reclasses? >> >> > ``` range.Date <- function(x, ..., na.rm = FALSE, finite >> > FALSE) { .Date(range(unclass(x), na.rm = na.rm, finite >> > finite), oldClass(x)) } ``` >> >> > This is similar to how `rep.Date()` works. >> >> > Thanks, Davis Vaughan >> >> > ______________________________________________ >> > R-devel at r-project.org mailing list >> > https://stat.ethz.ch/mailman/listinfo/r-devel