Github user sun-rui commented on a diff in the pull request:
https://github.com/apache/spark/pull/8920#discussion_r40746150
--- Diff: R/pkg/R/DataFrame.R ---
@@ -1848,3 +1848,62 @@ setMethod("crosstab",
sct <- callJMethod(statFunctions, "crosstab", col1, col2)
collect(dataFrame(sct))
})
+
+#' Sort
+#'
+#' Sort a DataFrame by the specified column(s).
+#'
+#' @param x A DataFrame to be sorted.
+#' @param by A character column indicating the field to sort on.
+#' if the column names are specified as Column object arrange
function
+#' can be used instead
+#' @param decreasing Orderings for each sorting column
+#' @param ... Additional sorting fields
+#' @return A DataFrame where elements are sorted by input sorting columns.
+#' @rdname sort
+#' @name sort
+#' @aliases orderby
+#' @export
+#' @examples
+#'\dontrun{
+#' sc <- sparkR.init()
+#' sqlContext <- sparkRSQL.init(sc)
+#' path <- "path/to/file.json"
+#' df <- jsonFile(sqlContext, path)
+#' sort(df, col="col1")
+#' sort(df, decreasing=FALSE, "col2")
+#' sort(df, decreasing=TRUE, "col1")
+#' sort(df, c(TRUE,FALSE), "col1","col2")
+#' }
+setMethod("sort",
+ signature(x = "DataFrame"),
+ function(x, decreasing=FALSE, col, ...) {
+
+ # all sorting columns
+ by <- c(col, ...)
+ if (length(decreasing) == 1){
+ # in case only 1 boolean argument - decreasing value is
specified,
+ # it will be used for all columns
+ decreasing <- rep(decreasing,length(by))
+ } else if (length(decreasing) != length(by)){
+ stop("Arguments 'col' and 'decreasing' must have the same
length")
+ }
+
+ # builds a list of columns of type Column
+ # example: [[1]] Column Species ASC
+ # [[2]] Column Petal_Length DESC
+ columns <- lapply(seq_len(length(decreasing)), function(i){
+ if (decreasing[[i]]){
+ desc(getColumn(x, by[[i]]))
+ }else{
+ asc(getColumn(x, by[[i]]))
+ }
+ })
+
--- End diff --
The following logic can be replaced by:
do.call("arrange", x, columns)
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