Preserve names in as.IDate() and as.ITime()

NEWS.md

@@ -58,6 +58,8 @@
 
 12. `print.data.table()` now truncates long character columns and list-column summaries by default to avoid horizontal console overflow, [#7718](https://github.com/Rdatatable/data.table/issues/7718). When `datatable.prettyprint.char` is `NULL` (the default), the truncation limit is now dynamically calculated based on the available console width. Use `options(datatable.prettyprint.char=Inf)` for the old default behavior (never truncate). Thanks @tdhock for the report and @venom1204 for the fix.
 
+13. `as.IDate()` and `as.ITime()` now preserve names, matching base `as.Date()` behavior, [#7252](https://github.com/Rdatatable/data.table/issues/7252). Thanks @DavisVaughan for the report and @venom1204 for the PR.
+
 ### Notes
 
 1. {data.table} now depends on R 3.5.0 (2018).

R/IDateTime.R

@@ -5,6 +5,11 @@
 
 as.IDate = function(x, ...) UseMethod("as.IDate")
 
+copy_names = function(ans, nm) {
+  if (!is.null(nm)) setattr(ans, "names", nm)
+  ans
+}
+
 as.IDate.default = function(x, ..., tz = attr(x, "tzone", exact=TRUE)) {
   if (is.null(tz)) tz = "UTC"
   if (is.character(x)) {
@@ -15,32 +20,36 @@ as.IDate.default = function(x, ..., tz = attr(x, "tzone", exact=TRUE)) {
 }
 
 as.IDate.numeric = function(x, origin = "1970-01-01", ...) {
+  nm = names(x)
   if (origin=="1970-01-01") {
-    # standard epoch
     x = as.integer(x)
     class(x) = c("IDate", "Date")
     # We used to use structure() here because class(x)<- copied several times in R before v3.1.0
     # Since R 3.1.0 improved class()<- and data.table's oldest oldest supported R is now 3.1.0, we can use class<- again
     # structure() contains a match() and replace for specials, which we don't need.
     # class()<- ensures at least 1 shallow copy as appropriate is returned.
-    x
+    copy_names(x, nm)
   } else {
-    # only call expensive as.IDate.character if we have to
-    as.IDate(origin, ...) + as.integer(x)
+    ans = as.IDate(origin, ...) + as.integer(x)
+    copy_names(ans, nm)
   }
 }
 
 as.IDate.Date = function(x, ...) {
-  x = as.integer(x)                 # if already integer, x will be left unchanged as the original input
-  class(x) = c("IDate", "Date")     # class()<- will copy if as.integer() did not create, and may not if it did we hope
-  x                                 # always return a new object
+  nm = names(x)
+  x = as.integer(x)
+  class(x) = c("IDate", "Date")
+  copy_names(x, nm)
 }
 
 as.IDate.POSIXct = function(x, tz = attr(x, "tzone", exact=TRUE), ...) {
-  if (is_utc(tz))
-    (setattr(as.integer(as.numeric(x) %/% 86400L), "class", c("IDate", "Date")))  # %/% returns new object so can use setattr() on it; wrap with () to return visibly
-  else
+  if (is_utc(tz)) {
+    ans = as.integer(as.numeric(x) %/% 86400L)
+    setattr(ans, "class", c("IDate", "Date"))
+    copy_names(ans, names(x))
+  } else {
     as.IDate(as.Date(x, tz =  tz %||% '', ...))
+  }
 }
 
 as.IDate.IDate = function(x, ...) x
@@ -155,13 +164,19 @@ as.ITime.POSIXct = function(x, tz = attr(x, "tzone", exact=TRUE), ...) {
 }
 
 as.ITime.numeric = function(x, ms = 'truncate', ...) {
+  nm = names(x)
   secs = clip_msec(x, ms) %% 86400L # the %% here ensures a local copy is obtained; the truncate as.integer() may not copy
-  (setattr(secs, "class", "ITime"))
+  setattr(secs, "class", "ITime")
+  copy_names(secs, nm)
 }
 
 as.ITime.character = function(x, format, ...) {
+  nm = names(x)
   x = unclass(x)
-  if (!missing(format)) return(as.ITime(strptime(x, format = format, ...), ...))
+  if (!missing(format)) {
+    ans = as.ITime(strptime(x, format = format, ...), ...)
+    return(copy_names(ans, nm))
+  }
   # else allow for mixed formats, such as test 1189 where seconds are caught despite varying format
   y = strptime(x, format = "%H:%M:%OS", ...)
   w = which(is.na(y))
@@ -181,12 +196,16 @@ as.ITime.character = function(x, format, ...) {
       w = w[!nna]
     }
   }
-  as.ITime(y, ...)
+  ans = as.ITime(y, ...)
+  copy_names(ans, nm)
 }
 
 as.ITime.POSIXlt = function(x, ms = 'truncate', ...) {
+  nm = names(x)
   secs = clip_msec(x$sec, ms)
-  (setattr(with(x, secs + min * 60L + hour * 3600L), "class", "ITime"))  # () wrap to return visibly
+  ans = with(x, secs + min * 60L + hour * 3600L)
+  setattr(ans, "class", "ITime")
+  copy_names(ans, nm)
 }
 
 as.ITime.times = function(x, ms = 'truncate', ...) {

inst/tests/tests.Rraw

@@ -21669,3 +21669,15 @@ test(2375.3, print(data.table(x=c("short", "abcdefghijklmnopqrstuvwxyz"))), outp
 test(2375.4, print(data.table(x="abcdefghijklmnopqrstuvwxyz")), output="abcdefghijklmnopqrstuvwxyz", options=list(width=200, datatable.prettyprint.char=NULL))
 test(2375.5, print(data.table(id=1L, score=99.1, txt="abcdefghijklmnopqrstuvwxyz")), output="abcdefghijklmn...", options=list(width=20, datatable.prettyprint.char=NULL))
 test(2375.6, print(data.table(x=rep("ABCDEFGHIJKLMNOPQRSTUVWXYZ", 1e6)), topn=1), output="1000000: ABCDEFGHIJKLM...", options=list(width=25, datatable.prettyprint.char=NULL))
+
+# #7252 as.IDate()/as.ITime preserve names
+test(2376.01, names(as.IDate(c(a = "2019-01-01"))), "a")
+test(2376.02, names(c(a = as.IDate("2019-01-01"))), "a")
+test(2376.03, names(as.ITime(c(a = "12:00:00"))), "a")
+test(2376.04, names(as.IDate(structure(as.POSIXct("2019-01-01 12:00:00"), names = "a"))), "a")
+test(2376.05, names(as.ITime(structure(3600, names = "a"))), "a")
+test(2376.06, names(as.IDate(c(a = 18000))), "a")
+test(2376.07, names(as.IDate(c(a = 1), origin = "2020-01-01")), "a")
+test(2376.08, names(as.ITime(c(a = "12-00-00"), format = "%H-%M-%S")), "a")
+test(2376.09, names(as.IDate(as.POSIXct(c(a = "2019-01-01"), tz="UTC"))), "a")
+test(2376.10, names(as.IDate(as.POSIXct(c(a = "2019-01-01"), tz="America/New_York"))), "a")