From ef70cee9a64c0d2e274cf228e27723083dbd691e Mon Sep 17 00:00:00 2001
From: actuaryzhang <actuaryzhang10@gmail.com>
Date: Tue, 13 Jun 2017 10:00:27 -0700
Subject: [PATCH 1/2] add trunc function to SparkR SQL

---
 R/pkg/NAMESPACE                       |  1 +
 R/pkg/R/functions.R                   | 28 +++++++++++++++++++++++++++
 R/pkg/tests/fulltests/test_sparkSQL.R |  2 ++
 3 files changed, 31 insertions(+)

diff --git a/R/pkg/NAMESPACE b/R/pkg/NAMESPACE
index 4e3fe00a2e9b..229de4a997ee 100644
--- a/R/pkg/NAMESPACE
+++ b/R/pkg/NAMESPACE
@@ -357,6 +357,7 @@ exportMethods("%<=>%",
               "to_utc_timestamp",
               "translate",
               "trim",
+              "trunc",
               "unbase64",
               "unhex",
               "unix_timestamp",
diff --git a/R/pkg/R/functions.R b/R/pkg/R/functions.R
index 06a90192bb12..a6adcf4e9e59 100644
--- a/R/pkg/R/functions.R
+++ b/R/pkg/R/functions.R
@@ -4015,3 +4015,31 @@ setMethod("input_file_name", signature("missing"),
             jc <- callJStatic("org.apache.spark.sql.functions", "input_file_name")
             column(jc)
           })
+
+#' trunc
+#'
+#' Returns date truncated to the unit specified by the format.
+#'
+#' @param x Column to compute on.
+#' @param format string used for specify the truncation method. For example, "year", "yyyy",
+#' "yy" for truncate by year, or "month", "mon", "mm" for truncate by month.
+#'
+#' @rdname trunc
+#' @name trunc
+#' @family date time functions
+#' @aliases trunc,Column-method
+#' @export
+#' @examples
+#' \dontrun{
+#' trunc(df$c, "year")
+#' trunc(df$c, "yy")
+#' trunc(df$c, "month")
+#' trunc(df$c, "mon")
+#' }
+#' @note trunc since 2.3.0
+setMethod("trunc",
+          signature(x = "Column"),
+          function(x, format) {
+            jc <- callJStatic("org.apache.spark.sql.functions", "trunc", x@jc, format)
+            column(jc)
+          })
diff --git a/R/pkg/tests/fulltests/test_sparkSQL.R b/R/pkg/tests/fulltests/test_sparkSQL.R
index af529067f43e..911b73b9ee55 100644
--- a/R/pkg/tests/fulltests/test_sparkSQL.R
+++ b/R/pkg/tests/fulltests/test_sparkSQL.R
@@ -1382,6 +1382,8 @@ test_that("column functions", {
   c20 <- to_timestamp(c) + to_timestamp(c, "yyyy") + to_date(c, "yyyy")
   c21 <- posexplode_outer(c) + explode_outer(c)
   c22 <- not(c)
+  c23 <- trunc(c, "year") + trunc(c, "yyyy") + trunc(c, "yy") +
+    trunc(c, "month") + trunc(c, "mon") + trunc(c, "mm")
 
   # Test if base::is.nan() is exposed
   expect_equal(is.nan(c("a", "b")), c(FALSE, FALSE))

From 797c3d0e77c7c91d499a55036e43c7ebfd6e9ced Mon Sep 17 00:00:00 2001
From: actuaryzhang <actuaryzhang10@gmail.com>
Date: Thu, 15 Jun 2017 10:56:59 -0700
Subject: [PATCH 2/2] force format to be character

---
 R/pkg/R/functions.R | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/R/pkg/R/functions.R b/R/pkg/R/functions.R
index a6adcf4e9e59..7128c3b9adff 100644
--- a/R/pkg/R/functions.R
+++ b/R/pkg/R/functions.R
@@ -4040,6 +4040,7 @@ setMethod("input_file_name", signature("missing"),
 setMethod("trunc",
           signature(x = "Column"),
           function(x, format) {
-            jc <- callJStatic("org.apache.spark.sql.functions", "trunc", x@jc, format)
+            jc <- callJStatic("org.apache.spark.sql.functions", "trunc",
+                              x@jc, as.character(format))
             column(jc)
           })