Preserve ordered attribute in expand.

Fixes tidyverse#165
imanns · May 16, 2016 · fd505e0 · fd505e0
1 parent 2876b5d
commit fd505e0
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diff --git a/NEWS.md b/NEWS.md
@@ -1,5 +1,8 @@
 # tidyr 0.4.1.9000
 
+* `expand()` (and hence `complete()`) preserves the ordered attribute of 
+  factors (#165).
+
 * `complete()` preserves grouping created by dplyr (#168).
 
 * `nest()` now returns correct output if every variable is nested (#186).

diff --git a/R/spread.R b/R/spread.R
@@ -160,7 +160,7 @@ ulevels <- function(x) {
   if (is.factor(x)) {
     x <- addNA(x, ifany = TRUE)
     levs <- levels(x)
-    factor(levs, levels = levs)
+    factor(levs, levels = levs, ordered = is.ordered(x))
   } else {
     sort(unique(x))
   }

diff --git a/tests/testthat/test-expand.R b/tests/testthat/test-expand.R
@@ -53,3 +53,9 @@ test_that("expand respects groups", {
   expect_equal(out$data[[2]], dplyr::data_frame(b = 1L, c = 1L))
 })
 
+test_that("preserves ordered factors", {
+  df <- dplyr::data_frame(a = ordered("a"))
+  out <- expand(df, a)
+
+  expect_equal(df$a, ordered("a"))
+})