标签：转换 val ------------------ frame dataFrame DataFrame 算子 println select
val sparkConf = new SparkConf().setMaster("local[2]").setAppName("tran")
val sparkSession = SparkSession.builder().config(sparkConf).getOrCreate()
val seq:Seq[Student] = Array(Student("zs",20,"男"),Student("ls",21,"女"),Student("ww",22,"男"))
val rdd:RDD[Student] = sparkSession.sparkContext.makeRDD(seq)
val dataFrame:DataFrame = sparkSession.createDataFrame(rdd,classOf[Student])
case class Student(@BeanProperty var name:String,@BeanProperty var age:Int,@BeanProperty var sex:String)
limit
def limitOpt(dataFrame: DataFrame): Unit = {
println("------------------limit操作开始------------------")
// select name,age from student limit 2
val frame: DataFrame = dataFrame.limit(2).select("name", "age")
frame.show()
println("------------------limit操作结束------------------")
}
where
def whereOpt(dataFrame: DataFrame) = {
// select * from student where age>21
println("------------------where操作开始------------------")
val frame = dataFrame.where("age > 21").select("*")
frame.show()
println("------------------where操作结束------------------")
println("------------------filter操作开始------------------")
val frame1 = dataFrame.filter("age > 21").select("*")
frame1.show()
println("------------------filter操作结束------------------")
}
select
def selectOpt(dataFrame: DataFrame) = {
println("------------------select操作开始------------------")
val frame = dataFrame.select("name", "age")
frame.show()
println("------------------select操作结束------------------")
}
def selectExprOpt(dataFrame: DataFrame) = {
println("------------------selectExpr操作开始------------------")
val frame = dataFrame.selectExpr("name as na", "age as ag")
frame.show()
println("------------------selectExpr操作结束------------------")
}
标签：转换,
val,
------------------,
frame,
dataFrame,
DataFrame,
算子,
println,
select
From： https://www.cnblogs.com/jsqup/p/16637891.html