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author | Yu ISHIKAWA <yuu.ishikawa@gmail.com> | 2015-08-18 20:27:36 -0700 |
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committer | Shivaram Venkataraman <shivaram@cs.berkeley.edu> | 2015-08-18 20:27:36 -0700 |
commit | bf32c1f7f47dd907d787469f979c5859e02ce5e6 (patch) | |
tree | b6ff3e44b631be5eb60e1f0d1850b019b0c1b2b4 /R | |
parent | a5b5b936596ceb45f5f5b68bf1d6368534fb9470 (diff) | |
download | spark-bf32c1f7f47dd907d787469f979c5859e02ce5e6.tar.gz spark-bf32c1f7f47dd907d787469f979c5859e02ce5e6.tar.bz2 spark-bf32c1f7f47dd907d787469f979c5859e02ce5e6.zip |
[SPARK-10075] [SPARKR] Add `when` expressino function in SparkR
- Add `when` and `otherwise` as `Column` methods
- Add `When` as an expression function
- Add `%otherwise%` infix as an alias of `otherwise`
Since R doesn't support a feature like method chaining, `otherwise(when(condition, value), value)` style is a little annoying for me. If `%otherwise%` looks strange for shivaram, I can remove it. What do you think?
### JIRA
[[SPARK-10075] Add `when` expressino function in SparkR - ASF JIRA](https://issues.apache.org/jira/browse/SPARK-10075)
Author: Yu ISHIKAWA <yuu.ishikawa@gmail.com>
Closes #8266 from yu-iskw/SPARK-10075.
Diffstat (limited to 'R')
-rw-r--r-- | R/pkg/NAMESPACE | 2 | ||||
-rw-r--r-- | R/pkg/R/column.R | 14 | ||||
-rw-r--r-- | R/pkg/R/functions.R | 14 | ||||
-rw-r--r-- | R/pkg/R/generics.R | 8 | ||||
-rw-r--r-- | R/pkg/inst/tests/test_sparkSQL.R | 7 |
5 files changed, 45 insertions, 0 deletions
diff --git a/R/pkg/NAMESPACE b/R/pkg/NAMESPACE index 607aef2611..8fa12d5ade 100644 --- a/R/pkg/NAMESPACE +++ b/R/pkg/NAMESPACE @@ -152,6 +152,7 @@ exportMethods("abs", "n_distinct", "nanvl", "negate", + "otherwise", "pmod", "quarter", "reverse", @@ -182,6 +183,7 @@ exportMethods("abs", "unhex", "upper", "weekofyear", + "when", "year") exportClasses("GroupedData") diff --git a/R/pkg/R/column.R b/R/pkg/R/column.R index 328f595d08..5a07ebd308 100644 --- a/R/pkg/R/column.R +++ b/R/pkg/R/column.R @@ -203,3 +203,17 @@ setMethod("%in%", jc <- callJMethod(x@jc, "in", table) return(column(jc)) }) + +#' otherwise +#' +#' If values in the specified column are null, returns the value. +#' Can be used in conjunction with `when` to specify a default value for expressions. +#' +#' @rdname column +setMethod("otherwise", + signature(x = "Column", value = "ANY"), + function(x, value) { + value <- ifelse(class(value) == "Column", value@jc, value) + jc <- callJMethod(x@jc, "otherwise", value) + column(jc) + }) diff --git a/R/pkg/R/functions.R b/R/pkg/R/functions.R index e606b20570..366c230e1e 100644 --- a/R/pkg/R/functions.R +++ b/R/pkg/R/functions.R @@ -165,3 +165,17 @@ setMethod("n", signature(x = "Column"), function(x) { count(x) }) + +#' when +#' +#' Evaluates a list of conditions and returns one of multiple possible result expressions. +#' For unmatched expressions null is returned. +#' +#' @rdname column +setMethod("when", signature(condition = "Column", value = "ANY"), + function(condition, value) { + condition <- condition@jc + value <- ifelse(class(value) == "Column", value@jc, value) + jc <- callJStatic("org.apache.spark.sql.functions", "when", condition, value) + column(jc) + }) diff --git a/R/pkg/R/generics.R b/R/pkg/R/generics.R index 5c1cc98fd9..338b32e648 100644 --- a/R/pkg/R/generics.R +++ b/R/pkg/R/generics.R @@ -651,6 +651,14 @@ setGeneric("rlike", function(x, ...) { standardGeneric("rlike") }) #' @export setGeneric("startsWith", function(x, ...) { standardGeneric("startsWith") }) +#' @rdname column +#' @export +setGeneric("when", function(condition, value) { standardGeneric("when") }) + +#' @rdname column +#' @export +setGeneric("otherwise", function(x, value) { standardGeneric("otherwise") }) + ###################### Expression Function Methods ########################## diff --git a/R/pkg/inst/tests/test_sparkSQL.R b/R/pkg/inst/tests/test_sparkSQL.R index 83caba8b5b..841de657df 100644 --- a/R/pkg/inst/tests/test_sparkSQL.R +++ b/R/pkg/inst/tests/test_sparkSQL.R @@ -727,6 +727,13 @@ test_that("greatest() and least() on a DataFrame", { expect_equal(collect(select(df, least(df$a, df$b)))[, 1], c(1, 3)) }) +test_that("when() and otherwise() on a DataFrame", { + l <- list(list(a = 1, b = 2), list(a = 3, b = 4)) + df <- createDataFrame(sqlContext, l) + expect_equal(collect(select(df, when(df$a > 1 & df$b > 2, 1)))[, 1], c(NA, 1)) + expect_equal(collect(select(df, otherwise(when(df$a > 1, 1), 0)))[, 1], c(0, 1)) +}) + test_that("group by", { df <- jsonFile(sqlContext, jsonPath) df1 <- agg(df, name = "max", age = "sum") |