从Scala中的数组生成.csv文件

我在Scala中有两个元组，其形式如下：

val array1 = (bucket1, Seq((dateA, Amount11), (dateB, Amount12), (dateC, Amount13))) 
val array2 = (bucket2, Seq((dateA, Amount21), (dateB, Amount22), (dateC, Amount23)))

在Scala中创建

.csv

文件的最快方法是什么：

date*

是枢轴

bucket*

是列名

金额*

填写表格

它需要看起来像这样：

日期：1号，2号

日期-金额11-金额21

日期buuuuuuuuuuuo

---

dateC\uuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuu

scala> val array1 = ("bucket1", Seq(("dateA", "Amount11"), ("dateB", "Amount12"), ("dateC", "Amount13"))) 
array1: (String, Seq[(String, String)]) =
          (bucket1,List((dateA,Amount11), (dateB,Amount12), (dateC,Amount13)))

scala> val array2 = ("bucket2", Seq(("dateA", "Amount21"), ("dateB", "Amount22"), ("dateC", "Amount23")))
array2: (String, Seq[(String, String)]) = 
          (bucket2,List((dateA,Amount21), (dateB,Amount22), (dateC,Amount23)))

// Single array to work with
scala> val arrays = List(array1, array2)
arrays: List[(String, Seq[(String, String)])] = List(
          (bucket1,List((dateA,Amount11), (dateB,Amount12), (dateC,Amount13))),
          (bucket2,List((dateA,Amount21), (dateB,Amount22), (dateC,Amount23)))
        )

---

// Split between buckets and the values
scala> val (buckets, values) = arrays.unzip
buckets: List[String] = List(bucket1, bucket2)
values: List[Seq[(String, String)]] = List(
          List((dateA,Amount11), (dateB,Amount12), (dateC,Amount13)),
          List((dateA,Amount21), (dateB,Amount22), (dateC,Amount23))
        )

// Format the data
// Note that this does not keep the 'dateX' order
scala> val grouped = values.flatten
                           .groupBy(_._1)
                           .map { case (date, list) => date::(list.map(_._2)) }
grouped: scala.collection.immutable.Iterable[List[String]] = List(
          List(dateC, Amount13, Amount23), 
          List(dateB, Amount12, Amount22),
          List(dateA, Amount11, Amount21)
        )

// Join everything, and add the "Dates" column in front of the buckets
scala> val table = ("Dates"::buckets)::grouped.toList
table: List[List[String]] = List(
          List(Dates, bucket1, bucket2),
          List(dateC, Amount13, Amount23),
          List(dateB, Amount12, Amount22),
          List(dateA, Amount11, Amount21)
        )

// Join the rows by ',' and the lines by "\n"
scala> val string = table.map(_.mkString(",")).mkString("\n")
string: String =
Dates,bucket1,bucket2
dateC,Amount13,Amount23
dateB,Amount12,Amount22
dateA,Amount11,Amount21