如何在 Scala 中使用地图并接收索引?

问题描述

是否有任何内置的 List/Sequence 的行为类似于 map 并提供元素的索引?

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

推荐答案

我相信您正在寻找 zipWithIndex?

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

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

你也有类似的变体:

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

或:

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

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