[SPARK-12044][SPARKR] Fix usage of isnan, isNaN

1, Add ```isNaN``` to ```Column``` for SparkR. ```Column``` should has three related variable functions: ```isNaN, isNull, isNotNull```.
2, Replace ```DataFrame.isNaN``` with ```DataFrame.isnan``` at SparkR side. Because ```DataFrame.isNaN``` has been deprecated and will be removed at Spark 2.0.
<del>3, Add ```isnull``` to ```DataFrame``` for SparkR. ```DataFrame``` should has two related functions: ```isnan, isnull```.<del>

cc shivaram sun-rui felixcheung

Author: Yanbo Liang <ybliang8@gmail.com>

Closes #10037 from yanboliang/spark-12044.

(cherry picked from commit b6e8e63)
Signed-off-by: Shivaram Venkataraman <shivaram@cs.berkeley.edu>

Author: yanboliang

R/pkg/R/column.R

@@ -56,7 +56,7 @@ operators <- list(
   "&" = "and", "|" = "or", #, "!" = "unary_$bang"
   "^" = "pow"
 )
-column_functions1 <- c("asc", "desc", "isNull", "isNotNull")
+column_functions1 <- c("asc", "desc", "isNaN", "isNull", "isNotNull")
 column_functions2 <- c("like", "rlike", "startsWith", "endsWith", "getField", "getItem", "contains")
 
 createOperator <- function(op) {

R/pkg/R/functions.R

@@ -537,19 +537,31 @@ setMethod("initcap",
             column(jc)
           })
 
-#' isNaN
+#' is.nan
 #'
-#' Return true iff the column is NaN.
+#' Return true if the column is NaN, alias for \link{isnan}
 #'
-#' @rdname isNaN
-#' @name isNaN
+#' @rdname is.nan
+#' @name is.nan
 #' @family normal_funcs
 #' @export
-#' @examples \dontrun{isNaN(df$c)}
-setMethod("isNaN",
+#' @examples
+#' \dontrun{
+#' is.nan(df$c)
+#' isnan(df$c)
+#' }
+setMethod("is.nan",
+          signature(x = "Column"),
+          function(x) {
+            isnan(x)
+          })
+
+#' @rdname is.nan
+#' @name isnan
+setMethod("isnan",
           signature(x = "Column"),
           function(x) {
-            jc <- callJStatic("org.apache.spark.sql.functions", "isNaN", x@jc)
+            jc <- callJStatic("org.apache.spark.sql.functions", "isnan", x@jc)
             column(jc)
           })
 

R/pkg/R/generics.R

@@ -625,6 +625,10 @@ setGeneric("getField", function(x, ...) { standardGeneric("getField") })
 #' @export
 setGeneric("getItem", function(x, ...) { standardGeneric("getItem") })
 
+#' @rdname column
+#' @export
+setGeneric("isNaN", function(x) { standardGeneric("isNaN") })
+
 #' @rdname column
 #' @export
 setGeneric("isNull", function(x) { standardGeneric("isNull") })
@@ -808,9 +812,9 @@ setGeneric("initcap", function(x) { standardGeneric("initcap") })
 #' @export
 setGeneric("instr", function(y, x) { standardGeneric("instr") })
 
-#' @rdname isNaN
+#' @rdname is.nan
 #' @export
-setGeneric("isNaN", function(x) { standardGeneric("isNaN") })
+setGeneric("isnan", function(x) { standardGeneric("isnan") })
 
 #' @rdname kurtosis
 #' @export

R/pkg/inst/tests/test_sparkSQL.R

@@ -883,7 +883,7 @@ test_that("column functions", {
   c2 <- avg(c) + base64(c) + bin(c) + bitwiseNOT(c) + cbrt(c) + ceil(c) + cos(c)
   c3 <- cosh(c) + count(c) + crc32(c) + exp(c)
   c4 <- explode(c) + expm1(c) + factorial(c) + first(c) + floor(c) + hex(c)
-  c5 <- hour(c) + initcap(c) + isNaN(c) + last(c) + last_day(c) + length(c)
+  c5 <- hour(c) + initcap(c) + last(c) + last_day(c) + length(c)
   c6 <- log(c) + (c) + log1p(c) + log2(c) + lower(c) + ltrim(c) + max(c) + md5(c)
   c7 <- mean(c) + min(c) + month(c) + negate(c) + quarter(c)
   c8 <- reverse(c) + rint(c) + round(c) + rtrim(c) + sha1(c)
@@ -894,6 +894,10 @@ test_that("column functions", {
   c13 <- lead("col", 1) + lead(c, 1) + lag("col", 1) + lag(c, 1)
   c14 <- cume_dist() + ntile(1) + corr(c, c1)
   c15 <- dense_rank() + percent_rank() + rank() + row_number()
+  c16 <- is.nan(c) + isnan(c) + isNaN(c)
+
+  # Test if base::is.nan() is exposed
+  expect_equal(is.nan(c("a", "b")), c(FALSE, FALSE))
 
   # Test if base::rank() is exposed
   expect_equal(class(rank())[[1]], "Column")