java vector 使用



2012-12-02 00:13 
youxin 
阅读(401
评论(0
编辑 
收藏 
举报

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> {}

版权声明:本文为youxin原创文章,遵循 CC 4.0 BY-SA 版权协议,转载请附上原文出处链接和本声明。
本文链接:https://www.cnblogs.com/youxin/archive/2012/12/02/2797848.html