1 files changed, 46 insertions, 0 deletions
diff --git a/src/arrow/r/R/dplyr-distinct.R b/src/arrow/r/R/dplyr-distinct.R
new file mode 100644
index 000000000..5dfcb641f
--- /dev/null
+++ b/src/arrow/r/R/dplyr-distinct.R
@@ -0,0 +1,46 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+# The following S3 methods are registered on load if dplyr is present
+
+distinct.arrow_dplyr_query <- function(.data, ..., .keep_all = FALSE) {
+  if (.keep_all == TRUE) {
+    # After ARROW-13993 is merged, we can implement this (ARROW-14045)
+    arrow_not_supported("`distinct()` with `.keep_all = TRUE`")
+  }
+
+  original_gv <- dplyr::group_vars(.data)
+  if (length(quos(...))) {
+    # group_by() calls mutate() if there are any expressions in ...
+    .data <- dplyr::group_by(.data, ..., .add = TRUE)
+    # `data %>% group_by() %>% summarise()` returns cols in order supplied
+    # but distinct() returns cols in dataset order, so sort group vars
+    .data$group_by_vars <- names(.data)[names(.data) %in% .data$group_by_vars]
+  } else {
+    # distinct() with no vars specified means distinct across all cols
+    .data <- dplyr::group_by(.data, !!!syms(names(.data)))
+  }
+
+  out <- dplyr::summarize(.data, .groups = "drop")
+  # distinct() doesn't modify group by vars, so restore the original ones
+  if (length(original_gv)) {
+    out$group_by_vars <- original_gv
+  }
+  out
+}
+
+distinct.Dataset <- distinct.ArrowTabular <- distinct.arrow_dplyr_query