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|
+--------+