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  • java vector 使用

    建立一个一维的vector:

    Vector<Double> v=new Vector<Double>();//实例一个v对象
    v.addElement();//在v中添加元素的方法
    v.elementAt(i);//取得v中索引为i的元素

    c++的 vector使用不需要new

    vector<int> v(10);

     

    vector向末尾添加元素有2种方法,add和addElement,有什么区别呢?

    add() comes from the List interface, which is part of the Java Collections Framework added in Java 1.2.Vector predates that and was retrofitted with it. The specific differences are:

    1. addElement() is synchronizedadd() isn't. In the Java Collections Framework, if you want these methods to be synchronized wrap the collection in Collections.synchronizedList(); and

    2. add() returns a boolean for success. addElement() has a void return type.

    The synchronized difference technically isn't part of the API. It's an implementation detail.

    Favour the use of the List methods. Like I said, if you want a synchronized List do:

    List<String> list =Collections.synchronizedList(newArrayList<String>());
    list.add("hello");
    via:http://stackoverflow.com/questions/3089969/difference-between-javas-vector-add-and-vector-addelement
    区别基本可以忽略。

    vector创建2维数组:
     
    Vector<Vector<Double>> v=new Vector<Vector<Double> >();
    //Example: get(0,2)
    Double d=v.get(0).get(2);
    new <? >表示泛型。
     
    从jdk5.0开始,新增了泛型功能。泛型可以使把你的定义的对象置于某个容器而不失去其类型。也可以定义泛型类,public class classname <T> {}
    
    
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  • 原文地址:https://www.cnblogs.com/youxin/p/2797848.html
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