spark 计算两个dataframe 的差集、交集、合集，只选择某一列来对比比较好。新建两个 dataframe ：

import org.apache.spark.{SparkConf, SparkContext}

import org.apache.spark.sql.SQLContext

def main(args: Array[String]): Unit = {

    val conf = new SparkConf().setAppName("TTyb").setMaster("local")

    val sc = new SparkContext(conf)

    val spark = new SQLContext(sc)

    val sentenceDataFrame = spark.createDataFrame(Seq(

      (1, "asf"),

      (2, "2143"),

      (3, "rfds")

    )).toDF("label", "sentence")

    sentenceDataFrame.show()

    val sentenceDataFrame1 = spark.createDataFrame(Seq(

      (1, "asf"),

      (2, "2143"),

      (4, "f8934y")

    )).toDF("label", "sentence")

    sentenceDataFrame1.show()

}

差集 except

val newDF = sentenceDataFrame1.select("sentence").except(sentenceDataFrame.select("sentence"))

newDF.show()

+--------+

|sentence|

+--------+

|f8934y |

+--------+

交集 intersect

val newDF = sentenceDataFrame1.select("sentence").intersect(sentenceDataFrame.select("sentence"))

newDF.show()

+--------+

|sentence|

+--------+

| asf|

| 2143|

+--------+

合集 union

val newDF = sentenceDataFrame1.select("sentence").union(sentenceDataFrame.select("sentence"))

newDF.show()

+--------+

|sentence|

+--------+

| asf|

| 2143|

| f8934y|

| asf|

| 2143|

| rfds|

+--------+

合集最好去一下重 distinct ：

val newDF = sentenceDataFrame1.select("sentence").union(sentenceDataFrame.select("sentence")).distinct()

newDF.show()

+--------+

|sentence|

+--------+

| rfds|

| asf|

| 2143|

| f8934y|

+--------+