Java 从队列转换为 ArrayList
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Convert from Queue to ArrayList
提问by user3120023
I want to change a queue containing numbers and operators into an ArrayList. I am coding in Java.
我想将包含数字和运算符的队列更改为 ArrayList。我正在用 Java 编码。
Currently my Queue is defined as follows:
目前我的队列定义如下：
Queue outputQueue = new LinkedList();
The queue currently contains the following data:
队列当前包含以下数据：
[1, 9, 3, /, 4, 3, -, 2, /, *, +]
I wish to do this mainly so i can use RPN to calculate the result of the calculation.
我希望这样做主要是为了我可以使用 RPN 来计算计算结果。
Is there a way to do this?
有没有办法做到这一点？
Thanks in advance for any help :)
在此先感谢您的帮助:)
回答by thatidiotguy
ArrayList list = new ArrayList(outputQueue);
回答by Prabhakaran Ramaswamy
Do like this
这样做
List list = new ArrayList(outputQueue);
回答by Brinnis
While the other answers are the correct way to create an ArrayList. You could simply cast it to a List. This would leave the same underlying data structure (LinkedList) but you can use it as a List then.
而其他答案是创建ArrayList. 您可以简单地将其强制转换为List. 这将保留相同的底层数据结构 ( LinkedList)，但您可以将其用作 List。
Queue outputQueue = new LinkedList();
List list = (List)outputQueue;
Weather or not this is a better way to do what you need depends on how you are using the List. You have to decide if the cost of create a new ArrayListis worth the the potential speed increase in accessing your data. Take a look at When to use LinkedList<> over ArrayList<>?.
天气与否这是做您需要的更好的方法取决于您如何使用列表。您必须决定创建新的成本ArrayList是否值得提高访问数据的潜在速度。看看什么时候在 ArrayList<> 上使用 LinkedList<>？.
回答by Chaitanya
Code like this
像这样的代码
Queue outputQueue = new LinkedList();
outputQueue.add("1");
outputQueue.add("9");
outputQueue.add("3");
outputQueue.add("/");
outputQueue.add("4");
outputQueue.add("3");
outputQueue.add("-");
outputQueue.add("2");
outputQueue.add("*");
outputQueue.add("+");
ArrayList arraylist = new ArrayList(outputQueue);
