[SPARK-20371][R] Add wrappers for collect_list and collect_set

## What changes were proposed in this pull request?

Adds wrappers for `collect_list` and `collect_set`.

## How was this patch tested?

Unit tests, `check-cran.sh`

Author: zero323 <zero323@users.noreply.github.com>

Closes #17672 from zero323/SPARK-20371.

Author: zero323

R/pkg/NAMESPACE

@@ -203,6 +203,8 @@ exportMethods("%in%",
               "cbrt",
               "ceil",
               "ceiling",
+              "collect_list",
+              "collect_set",
               "column",
               "concat",
               "concat_ws",

R/pkg/R/functions.R

@@ -3705,3 +3705,43 @@ setMethod("create_map",
             jc <- callJStatic("org.apache.spark.sql.functions", "map", jcols)
             column(jc)
           })
+
+#' collect_list
+#'
+#' Creates a list of objects with duplicates.
+#'
+#' @param x Column to compute on
+#'
+#' @rdname collect_list
+#' @name collect_list
+#' @family agg_funcs
+#' @aliases collect_list,Column-method
+#' @export
+#' @examples \dontrun{collect_list(df$x)}
+#' @note collect_list since 2.3.0
+setMethod("collect_list",
+          signature(x = "Column"),
+          function(x) {
+            jc <- callJStatic("org.apache.spark.sql.functions", "collect_list", x@jc)
+            column(jc)
+          })
+
+#' collect_set
+#'
+#' Creates a list of objects with duplicate elements eliminated.
+#'
+#' @param x Column to compute on
+#'
+#' @rdname collect_set
+#' @name collect_set
+#' @family agg_funcs
+#' @aliases collect_set,Column-method
+#' @export
+#' @examples \dontrun{collect_set(df$x)}
+#' @note collect_set since 2.3.0
+setMethod("collect_set",
+          signature(x = "Column"),
+          function(x) {
+            jc <- callJStatic("org.apache.spark.sql.functions", "collect_set", x@jc)
+            column(jc)
+          })

R/pkg/R/generics.R

@@ -918,6 +918,14 @@ setGeneric("cbrt", function(x) { standardGeneric("cbrt") })
 #' @export
 setGeneric("ceil", function(x) { standardGeneric("ceil") })
 
+#' @rdname collect_list
+#' @export
+setGeneric("collect_list", function(x) { standardGeneric("collect_list") })
+
+#' @rdname collect_set
+#' @export
+setGeneric("collect_set", function(x) { standardGeneric("collect_set") })
+
 #' @rdname column
 #' @export
 setGeneric("column", function(x) { standardGeneric("column") })
@@ -1358,6 +1366,7 @@ setGeneric("window", function(x, ...) { standardGeneric("window") })
 #' @export
 setGeneric("year", function(x) { standardGeneric("year") })
 
+
 ###################### Spark.ML Methods ##########################
 
 #' @rdname fitted

R/pkg/inst/tests/testthat/test_sparkSQL.R

@@ -1731,6 +1731,28 @@ test_that("group by, agg functions", {
   expect_true(abs(sd(1:2) - 0.7071068) < 1e-6)
   expect_true(abs(var(1:5, 1:5) - 2.5) < 1e-6)
 
+  # Test collect_list and collect_set
+  gd3_collections_local <- collect(
+    agg(gd3, collect_set(df8$age), collect_list(df8$age))
+  )
+
+  expect_equal(
+    unlist(gd3_collections_local[gd3_collections_local$name == "Andy", 2]),
+    c(30)
+  )
+
+  expect_equal(
+    unlist(gd3_collections_local[gd3_collections_local$name == "Andy", 3]),
+    c(30, 30)
+  )
+
+  expect_equal(
+    sort(unlist(
+      gd3_collections_local[gd3_collections_local$name == "Justin", 3]
+    )),
+    c(1, 19)
+  )
+
   unlink(jsonPath2)
   unlink(jsonPath3)
 })