如何在Scala中使用map并接收索引？ [英] How can I use map and receive an index as well in Scala?

问题描述

$ p $ / h2_lin>解决方案

我相信你正在寻找zipWithIndex？

  scala> val ls = List（Mary，had，a，little，lamb）
 scala> ls.zipWithIndex.foreach {case（e，i）=> println（i ++ e）} 
 0 Mary 
 1有
 2 a 
 3 little 
 4 lamb 
  

来自： http://www.artima.com/forums/flat.jsp?forum=283&thread=243570

您还有（（e，i）< - List（Mary，had，a）的变体如下：

  ，little，lamb）。zipWithIndex）println（i ++ e）
  

：

 列表（Mary，had，a，little，lamb）zipWithIndex。 foreach（（t）=> println（t._2 ++ t._1））
  

Is there any List/Sequence built-in that behaves like map and provides the element's index as well?

解决方案

I believe you're looking for zipWithIndex?

scala> val ls = List("Mary", "had", "a", "little", "lamb")
scala> ls.zipWithIndex.foreach{ case (e, i) => println(i+" "+e) }
0 Mary
1 had
2 a
3 little
4 lamb

From: http://www.artima.com/forums/flat.jsp?forum=283&thread=243570

You also have variations like:

for((e,i) <- List("Mary", "had", "a", "little", "lamb").zipWithIndex) println(i+" "+e)

or:

List("Mary", "had", "a", "little", "lamb").zipWithIndex.foreach( (t) => println(t._2+" "+t._1) )

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