uniqueN handle NULL, closes #1429

Rdatatable · Nov 10, 2015 · 51141fa · 51141fa
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commit 51141fa
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diff --git a/R/duplicated.R b/R/duplicated.R
@@ -91,7 +91,7 @@ anyDuplicated.data.table <- function(x, incomparables=FALSE, fromLast=FALSE, by=
 # of groups in a vector or data.table. Here by data.table, 
 # we really mean `.SD` - used in a grouping operation
 uniqueN <- function(x, by = if (is.data.table(x)) key(x) else NULL) {
-    if (!is.atomic(x) && !is.data.frame(x))
+    if (is.null(x) || (!is.atomic(x) && !is.data.frame(x)))
         return(length(unique(x)))
     if (is.atomic(x)) x = as_list(x)
     if (is.null(by)) by = seq_along(x)

diff --git a/README.md b/README.md
@@ -75,6 +75,8 @@
 
   16. `rleid()` does not affect attributes of input vector, [#1419](https://github.com/Rdatatable/data.table/issues/1419). Thanks @JanGorecki.
 
+  17. `uniqueN()` now handle NULL properly, [#1429](https://github.com/Rdatatable/data.table/issues/1429). Thanks @JanGorecki.
+
 #### NOTES
 
   1. Updated error message on invalid joins to reflect the new `on=` syntax, [#1368](https://github.com/Rdatatable/data.table/issues/1368). Thanks @MichaelChirico.

diff --git a/inst/tests/tests.Rraw b/inst/tests/tests.Rraw
@@ -7214,6 +7214,8 @@ test(1581.12, any(grepl("^GForce optimized j", opt2)), TRUE)
 
 options(datatable.optimize=optim)
 
+# handle NULL value correctly #1429
+test(1582, uniqueN(NULL), 0L)
 
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