/*import org.apache.spark.sql.functions._val sqlContext = new org.apache.spark.sql.SQLContext(sc)import sqlContext.implicits._*//*https://stackoverflow.com/questions/34614239/how-to-apply-a-function-to-a-column-of-a-spark-dataframehttps://jaceklaskowski.gitbooks.io/mastering-spark-sql/spark-sql-Column.htmlhttps://www.jianshu.com/p/833b72adb2b6*/import org.apache.spark.sql.functions.udfval df = Seq((1, "jeden"), (2, "dwa"), (3, "jerry"), (0,"tom")).toDF("number", "polish")scala> df.show+------+------+|number|polish|+------+------+|     1| jeden||     2|   dwa||     3| jerry||     0|   tom|+------+------+val label_class = udf((x:Int) => if(x>0) 1 else 0)scala> df.withColumn("number", label_class($"number")).show+------+------+|number|polish|+------+------+|     1| jeden||     1|   dwa||     1| jerry||     0|   tom|+------+------+scala> val data = df.withColumn("number", label_class($"number"))data: org.apache.spark.sql.DataFrame = [number: int, polish: string]scala> datares3: org.apache.spark.sql.DataFrame = [number: int, polish: string]scala> data.show+------+------+|number|polish|+------+------+|     1| jeden||     1|   dwa||     1| jerry||     0|   tom|+------+------+