如何改变RowMatrix到阵列中的Spark或将其导出为CSV？ [英] How to change RowMatrix into Array in Spark or export it as a CSV?

问题描述

我这有code Scala中：

  VAL垫：CoordinateMatrix =新CoordinateMatrix（数据）
VAL rowMatrix：RowMatrix = mat.toRowMatrix（）VAL SVD：SingularValueDecomposition [RowMatrix，矩阵] = rowMatrix.computeSVD（100，computeU = TRUE）VAL U：RowMatrix = svd.U //将U因素是RowMatrix。
VAL小号：矢量= svd.s //奇异值被存储在一个本地密载体。
VAL五：矩阵= svd.V //在V的因素是当地的密集矩阵。VAL uArray：数组[双] = U.toArray //不起作用，因为没有在RowMatrix型功能的toArray
VAL sArray：数组[双] = S.toArray //好工作
VAL VARRAY：数组[双] = V.toArray //好工作
 

我怎样才能改变的 U 的成的 uArray 的或相似的类型，可以打印出到CSV文件？

解决方案

这是一个基本的操作，这里是你必须做的考虑到U是RowMatrix如下内容：

  VAL U = svd.U
 

  

行（）是一个RowMatrix方法，它允许您从RowMatrix按行获得RDD。

你只需要在你的应用RowMatrix行和映射RDD [矢量]创建，你会连接成一个字符串创建RDD [字符串]数组。

  VAL RDD = U.rows.map（X =＆GT; x.toArray.mkString（））
 

所有你必须​​现在就做保存RDD：

  rdd.saveAsTextFile（路径）
 

I've got this code in Scala:

val mat: CoordinateMatrix = new CoordinateMatrix(data)
val rowMatrix: RowMatrix = mat.toRowMatrix()

val svd: SingularValueDecomposition[RowMatrix, Matrix] = rowMatrix.computeSVD(100, computeU = true)

val U: RowMatrix = svd.U // The U factor is a RowMatrix.
val S: Vector = svd.s // The singular values are stored in a local dense vector.
val V: Matrix = svd.V // The V factor is a local dense matrix.

val uArray: Array[Double] = U.toArray // doesn't work, because there is not toArray function in RowMatrix type
val sArray: Array[Double] = S.toArray // works good
val vArray: Array[Double] = V.toArray // works good

How can I change U into uArray or similar type, that could be printed out into CSV file?

解决方案

That's a basic operation, here is what you have to do considering that U is a RowMatrix as following :

val U = svd.U

rows() is a RowMatrix method that allows you to get an RDD from your RowMatrix by row.

You'll just need to apply rows on your RowMatrix and map the RDD[Vector] to create an Array that you would concatenate into a string creating an RDD[String].

val rdd = U.rows.map( x => x.toArray.mkString(","))

All you'll have to do now it to save the RDD :

rdd.saveAsTextFile(path)

这篇关于如何改变RowMatrix到阵列中的Spark或将其导出为CSV？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！