Merge branch 'r-0.7.6' (early part)

NEWS.md

@@ -119,6 +119,8 @@ To be released as 0.8.0
 * The MASS package is explicitly suggested to fix CRAN warnings on R-devel
   (#3657).
 
+* Set operations like `intersect()` and `setdiff()` reconstruct groups metadata (#3587).
+
 * Using namespaced calls to `base::sort()` and `base::unique()` from C++ code
   to avoid ambiguities when these functions are overridden (#3644).
 

R/dataframe.R

@@ -172,19 +172,42 @@ anti_join.data.frame <- function(x, y, by = NULL, copy = FALSE, ...) {
 # Set operations ---------------------------------------------------------------
 
 #' @export
-intersect.data.frame <- function(x, y, ...) intersect_data_frame(x, y)
+intersect.data.frame <- function(x, y, ...) {
+  out <- intersect_data_frame(x, y)
+  reconstruct_set(out, x)
+}
 
 #' @export
-union.data.frame <- function(x, y, ...) union_data_frame(x, y)
+union.data.frame <- function(x, y, ...) {
+  out <- union_data_frame(x, y)
+  reconstruct_set(out, x)
+}
 
 #' @export
-union_all.data.frame <- function(x, y, ...) bind_rows(x, y)
+union_all.data.frame <- function(x, y, ...) {
+  out <- bind_rows(x, y)
+  reconstruct_set(out, x)
+}
 
 #' @export
-setdiff.data.frame <- function(x, y, ...) setdiff_data_frame(x, y)
+setdiff.data.frame <- function(x, y, ...) {
+  out <- setdiff_data_frame(x, y)
+  reconstruct_set(out, x)
+}
 
 #' @export
-setequal.data.frame <- function(x, y, ...) equal_data_frame(x, y)
+setequal.data.frame <- function(x, y, ...) {
+  out <- equal_data_frame(x, y)
+  reconstruct_set(out, x)
+}
+
+reconstruct_set <- function(out, x) {
+  if (is_grouped_df(x)) {
+    out <- grouped_df_impl(out, group_vars(x), group_drop(x), FALSE)
+  }
+
+  out
+}
 
 #' @export
 distinct.data.frame <- function(.data, ..., .keep_all = FALSE) {

tests/testthat/test-sets.R

@@ -73,6 +73,10 @@ test_that("set operations reconstruct grouping metadata (#3587)", {
   df1 <- tibble(x = 1:4, g = rep(1:2, each = 2)) %>% group_by(g)
   df2 <- tibble(x = 3:6, g = rep(2:3, each = 2))
 
+  expect_equal(setdiff(df1, df2), filter(df1, x < 3))
+  expect_equal(intersect(df1, df2), filter(df1, x >= 3))
+  expect_equal(union(df1, df2), tibble(x = 1:6, g = rep(1:3, each = 2)) %>% group_by(g))
+
   expect_equal( setdiff(df1, df2) %>% group_rows(), list(1:2))
   expect_equal( intersect(df1, df2) %>% group_rows(), list(1:2))
   expect_equal( union(df1, df2) %>% group_rows(), list(5:6, 3:4, 1:2))