Apache spark case 在不同的列上有多个 when 子句

问题描述

鉴于以下结构:

val df = Seq("Color", "Shape", "Range","Size").map(Tuple1.apply).toDF("color")

val df1 = df.withColumn("Success", when($"color"<=> "white", "Diamond").otherwise(0))

我想在上面的 size > 10 和 Shape 列中再写一个 WHEN 条件值为菱形，则应将钻石"值插入到其他 0 列中.我尝试如下，但失败了

I want to write one more WHEN condition at above where size > 10 and Shape columnvalue is Rhombus then "Diamond" value should be inserted to the column else 0. I tried like below but it's failing

val df1 = df.withColumn("Success", when($"color" <=> "white", "Diamond").otherwise(0)).when($"size">10)

请建议我只使用带有 Scala 的数据框选项.带有 sqlContext 的 Spark-SQL 对我来说没有帮助.

Please suggest me with only dataframe option with scala. Spark-SQL with sqlContext is not helpful idea for me.

谢谢！

推荐答案

您可以链接 when 类似于 https://spark.apache.org/docs/latest/api/java/org/apache/spark/sql/Column.html#when-org.apache.spark.sql.Column-java.lang.Object-自 (1.4.0) 起可用

You can chain the when similar to the example in https://spark.apache.org/docs/latest/api/java/org/apache/spark/sql/Column.html#when-org.apache.spark.sql.Column-java.lang.Object-available since (1.4.0)

// Scala:
people.select(when(people("gender") === "male", 0)
 .when(people("gender") === "female", 1)
 .otherwise(2))

你的例子:

val df1 = df.withColumn("Success",
  when($"color" <=> "white", "Diamond")
  .when($"size" > 10 && $"shape" === "Rhombus", "Diamond")
  .otherwise(0))

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