Closes #1347. last() dispatches xts::last() properly.

R/last.R

@@ -4,10 +4,12 @@
 # We'd like last() on vectors to be fast, so that's a direct x[NROW(x)] as it was in data.table, otherwise use xts's.
 # If xts is loaded higher than data.table, xts::last will work but slower.
 last <- function(x, ...) {
-    if (nargs()==1L || !"package:xts" %in% search()) {
-        if (is.data.frame(x)) return(x[NROW(x),])
-        if (!length(x)) return(x) else return(x[[length(x)]])  # for vectors, [[ works like [
+    if (nargs()==1L) {
+        if (is.vector(x)) {
+        	if (!length(x)) return(x) else return(x[[length(x)]])  # for vectors, [[ works like [
+        } else if (is.data.frame(x)) return(x[NROW(x),])
     }
+    # fix with suggestion from Joshua, #1347
+    if (!"package:xts" %in% search()) tail(x,...)
     xts::last(x,...)   # UseMethod("last") doesn't find xts's methods, not sure what I did wrong.
 }
-

README.md

@@ -21,6 +21,8 @@
 
   2. `as.ITime(NA)` works as intended, [#1354](https://github.com/Rdatatable/data.table/issues/1354). Thanks @geneorama.
 
+  3. `last()` dispatches `xts::last()` properly again, [#1347](https://github.com/Rdatatable/data.table/issues/1347). Thanks to @JoshuaUlrich for spotting and suggesting the fix.
+
 #### NOTES
 
 

inst/tests/tests.Rraw

@@ -6952,6 +6952,14 @@ test(1557.4, dt[, .SD, .SDcols=paste0("index", 1:i)], dt[, .SD, .SDcols=index1:i
 # fix for #1354
 test(1558, as.ITime(NA), setattr(NA_integer_, 'class', 'ITime'))
 
+if (!"package:xts" %in% search()) {
+    # #1347, xts issue from Joshua
+    x = as.Date(1:5, origin="2015-01-01")
+    test(1559.1, last(x), tail(x, 1L))
+} else {
+    test(1559.2, last(.xts(1:3,1:3)), .xts(1:3, 1:3)[3, ])
+}
+
 ##########################