Question

如果有人用 mu子收集,那么,我是否能够复制脚ack,以便我能够用手套,在不改变原来的 st子的情况下分析其内容? 例如,我有一 st,其代码如下:

import scala.collection.mutable.Stack
var stack1 = new Stack[Int]
/** Code that pushes integers on stack1*/
var stackCopy = stack1
while (!stackCopy.isEmpty) {
    println(stackCopy.pop)
}

I want to use a while loop to print all elements in stack1. But when I make a copy and pop off that copy, the original stack (i.e. stack1) is also altered. I want to preserve the original stack, so how can I just get the contents, not the address?

Answer 1

你可以用来理解:

for( i <- stack1 ) { println(i) }

或简单称呼foreach 方法:

stack1 foreach println

如果您坚持使用<代码>,同时。例:

var is = stack1.toList
while( is.nonEmpty ) {
  println( is.head )
  is = is.tail
}

采用所有这些方法,将保留原来的部分。

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