7

在下面的代码中,在for理解内,我可以使用元组解引用来引用字符串和索引:

val strings = List("a", "b", "c")
for (stringWithIndex <- strings.zipWithIndex) {
  // Do something with stringWithIndex._1 (string) and stringWithIndex._2 (index)
}

Scala 语法中是否有任何方法可以在理解标头中拆分stringWithIndex部分(字符串和索引),以便代码读者不必怀疑and的值?forstringWithIndex._1stringWithIndex._2

我尝试了以下方法,但无法编译:

for (case (string, index) <- strings.zipWithIndex) {
  // Do something with string and index
}
4

2 回答 2

21

你几乎明白了:

scala> val strings = List("a", "b", "c")
strings: List[java.lang.String] = List(a, b, c)

scala> for ( (string, index) <- strings.zipWithIndex)
       | { println("str: "+string + " idx: "+index) }
str: a idx: 0
str: b idx: 1
str: c idx: 2

看,不需要case关键字。

于 2011-02-08T13:43:47.840 回答
7
strings.zipWithIndex.foreach{case(x,y) => println(x,y)}

资源:

(a,0)
(b,1)
(c,2)
于 2011-02-08T13:44:13.260 回答