1 files changed, 60 insertions, 0 deletions
diff --git a/src/arrow/r/R/dplyr-count.R b/src/arrow/r/R/dplyr-count.R
new file mode 100644
index 000000000..c567c285f
--- /dev/null
+++ b/src/arrow/r/R/dplyr-count.R
@@ -0,0 +1,60 @@
+# 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
+
+count.arrow_dplyr_query <- function(x, ..., wt = NULL, sort = FALSE, name = NULL) {
+  if (!missing(...)) {
+    out <- dplyr::group_by(x, ..., .add = TRUE)
+  } else {
+    out <- x
+  }
+  out <- dplyr::tally(out, wt = {{ wt }}, sort = sort, name = name)
+
+  # Restore original group vars
+  gv <- dplyr::group_vars(x)
+  if (length(gv)) {
+    out$group_by_vars <- gv
+  }
+
+  out
+}
+
+count.Dataset <- count.ArrowTabular <- count.arrow_dplyr_query
+
+#' @importFrom rlang sym :=
+tally.arrow_dplyr_query <- function(x, wt = NULL, sort = FALSE, name = NULL) {
+  check_name <- utils::getFromNamespace("check_name", "dplyr")
+  name <- check_name(name, dplyr::group_vars(x))
+
+  if (quo_is_null(enquo(wt))) {
+    out <- dplyr::summarize(x, !!name := n())
+  } else {
+    out <- dplyr::summarize(x, !!name := sum({{ wt }}, na.rm = TRUE))
+  }
+
+  if (sort) {
+    dplyr::arrange(out, desc(!!sym(name)))
+  } else {
+    out
+  }
+}
+
+tally.Dataset <- tally.ArrowTabular <- tally.arrow_dplyr_query
+
+# we don't want to depend on dplyr, but we refrence these above
+utils::globalVariables(c("n", "desc"))