Scala：使用scala

Question

我想以正确的格式显示数据，我有以下代码

val maplist=List(Map("id" -> "1", "Name" -> "divya"),
    Map("id" -> "2", "Name" -> "gaya")
)

val header=maplist.flatMap(_.keys).distinct
val data=maplist.map(_.values)
println(header.mkString(" "))
data.foreach(x => println(x.mkString(" ")))

显示为

id  Name
1   divya
2   gaya

但我想表现出来，我可能要使用df.show（）函数

+----+-----+
|Id  |Name |
+----+-----+
|1   |Divya|
|2   |gaya |
+----+-----+

Answer 1

如果您需要分隔符，则应使用mkString方法和更多参数，您可以查看API

  

mkString（start：String，sep：String，end：String）：String

     

在字符串中显示此可遍历或迭代器的所有元素   使用开始，结束和分隔符字符串。

  val separatorLine = "+----+-----+"
  val separator = "|"
  val maplist=List(Map("id" -> "1", "Name" -> "divya"),
    Map("id" -> "2", "Name" -> "gaya")
  )

  val header=maplist.flatMap(_.keys).distinct
  val data=maplist.map(_.values)
  println(separatorLine)
  println(header.mkString("|", " |", "|"))
  println(separatorLine)
  data.foreach(x => println(x.mkString("|", " |", "|")))
  println(separatorLine)

结果：

+----+-----+
|id |Name|
+----+-----+
|1 |divya|
|2 |gaya|
+----+-----+

更新：如果你想在每个字符串（例如5）中使用相同的长度，你可以做一个辅助方法，你需要在需要时附加空格：

 @tailrec
  private def appendElem(original : String, desiredLength: Int, c: Char): String = {
    if (original.length < desiredLength)
      appendElem(original + c, desiredLength, c)
    else {
      original
    }
  }
  val separator = "|"
  val maplist=List(Map("id" -> "1", "Name" -> "divya"),
    Map("id" -> "2", "Name" -> "gaya")
  )

  val separatorLine = List.fill(maplist.size)( "+").map(appendElem(_, 6,'-')).mkString+ "+"
  val header=maplist.flatMap(_.keys.map(key => appendElem(key, 5, ' '))).distinct
  val data=maplist.map(_.values)
  println(separatorLine)
  println(header.mkString("|", "|", "|"))
  println(separatorLine)
  data.map(x => x.map(y => appendElem(y, 5, ' '))).foreach(x => println(x.mkString("|", "|", "|")))
  println(separatorLine)

对于第二个版本，结果如​​下

+-----+-----+
|id   |Name |
+-----+-----+
|1    |divya|
|2    |gaya |
+-----+-----+