import org.apache.spark.ml.attribute.{Attribute, NumericAttribute}

import org.apache.spark.sql.SparkSession

import org.apache.spark.sql.types.StringType/**

* Created by shirukai on 2018/9/12

* 拆分列*/

objectSplitColTest {

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

val spark=SparkSession

.builder()

.appName(this.getClass.getSimpleName)

.master("local")

.getOrCreate()//从内存中创建DataFrame

import spark.implicits._

val df= Seq("Ming,20,15552211521", "hong,19,13287994007", "zhi,21,15552211523")

.toDF("value")

df.show()/**

* +-------------------+

* | value|

* +-------------------+

* |Ming,20,15552211521|

* |hong,19,13287994007|

* | zhi,21,15552211523|

* +-------------------+*/import org.apache.spark.sql.functions._//方法1： 使用内置函数split，然后遍历添加列

val separator = ","lazy val first=df.first()

val numAttrs=first.toString().split(separator).length

val attrs= Array.tabulate(numAttrs)(n => "col_" +n)//按指定分隔符拆分value列，生成splitCols列

var newDF = df.withColumn("splitCols", split($"value", separator))

attrs.zipWithIndex.foreach(x =>{

newDF= newDF.withColumn(x._1, $"splitCols".getItem(x._2))

})

newDF.show()/**

* +-------------------+--------------------+-----+-----+-----------+

* | value| splitCols|col_0|col_1| col_2|

* +-------------------+--------------------+-----+-----+-----------+

* |Ming,20,15552211521|[Ming, 20, 155522...| Ming| 20|15552211521|

* |hong,19,13287994007|[hong, 19, 132879...| hong| 19|13287994007|

* | zhi,21,15552211523|[zhi, 21, 1555221...| zhi| 21|15552211523|

* +-------------------+--------------------+-----+-----+-----------+*/

//方法2：使用udf函数创建多列，然后合并

val attributes: Array[Attribute] ={

val numAttrs=first.toString().split(separator).length//生成attributes

Array.tabulate(numAttrs)(i => NumericAttribute.defaultAttr.withName("value" + "_" +i))

}//创建多列数据

val fieldCols = attributes.zipWithIndex.map(x =>{

val assembleFunc=udf {

str: String=>str.split(separator)(x._2)

}

assembleFunc(df("value").cast(StringType)).as(x._1.name.get, x._1.toMetadata())

})//合并数据

df.select(col("*") +: fieldCols: _*).show()/**

* +-------------------+-------+-------+-----------+

* | value|value_0|value_1| value_2|

* +-------------------+-------+-------+-----------+

* |Ming,20,15552211521| Ming| 20|15552211521|

* |hong,19,13287994007| hong| 19|13287994007|

* | zhi,21,15552211523| zhi| 21|15552211523|

* +-------------------+-------+-------+-----------+*/}

}