Spark Equivalent of IF Then ELSE

Question

I have seen this question earlier here and I have took lessons from that. However I am not sure why I am getting an error when I feel it should work.

I want to crea

Answer 1

Conditional statement In Spark

• Using “when otherwise” on DataFrame
• Using “case when” on DataFrame
• Using && and || operator

---

import org.apache.spark.sql.functions.{when, _}
import spark.sqlContext.implicits._

val spark: SparkSession = SparkSession.builder().master("local[1]").appName("SparkByExamples.com").getOrCreate()

val data = List(("James ","","Smith","36636","M",60000),
        ("Michael ","Rose","","40288","M",70000),
        ("Robert ","","Williams","42114","",400000),
        ("Maria ","Anne","Jones","39192","F",500000),
        ("Jen","Mary","Brown","","F",0))

val cols = Seq("first_name","middle_name","last_name","dob","gender","salary")
val df = spark.createDataFrame(data).toDF(cols:_*)

1. Using “when otherwise” on DataFrame

Replace the value of gender with new value

val df1 = df.withColumn("new_gender", when(col("gender") === "M","Male")
      .when(col("gender") === "F","Female")
      .otherwise("Unknown"))

val df2 = df.select(col("*"), when(col("gender") === "M","Male")
      .when(col("gender") === "F","Female")
      .otherwise("Unknown").alias("new_gender"))

2. Using “case when” on DataFrame

val df3 = df.withColumn("new_gender",
  expr("case when gender = 'M' then 'Male' " +
                   "when gender = 'F' then 'Female' " +
                   "else 'Unknown' end"))

Alternatively,

val df4 = df.select(col("*"),
      expr("case when gender = 'M' then 'Male' " +
                       "when gender = 'F' then 'Female' " +
                       "else 'Unknown' end").alias("new_gender"))

3. Using && and || operator

val dataDF = Seq(
      (66, "a", "4"), (67, "a", "0"), (70, "b", "4"), (71, "d", "4"
      )).toDF("id", "code", "amt")
dataDF.withColumn("new_column",
       when(col("code") === "a" || col("code") === "d", "A")
      .when(col("code") === "b" && col("amt") === "4", "B")
      .otherwise("A1"))
      .show()

Output:

+---+----+---+----------+
| id|code|amt|new_column|
+---+----+---+----------+
| 66|   a|  4|         A|
| 67|   a|  0|         A|
| 70|   b|  4|         B|
| 71|   d|  4|         A|
+---+----+---+----------+