用Java检索TreeMap的大小
使用size()方法获取TreeMap的大小。
首先，创建一个TreeMap并向其中添加元素-
TreeMap<Integer,String> m = new TreeMap<Integer,String>(); m.put(1,"PHP"); m.put(2,"jQuery"); m.put(3,"JavaScript"); m.put(4,"Ruby"); m.put(5,"Java"); m.put(6,"AngularJS"); m.put(7,"ExpressJS");
计算上述TreeMap中的元素数，或使用size()如下所示的方法获取大小-
m.size()
要获取TreeMap的大小，以下是代码-
示例
import java.util.*;
public class Demo {
public static void main(String args[]) {
TreeMap<Integer,String> m = new TreeMap<Integer,String>();
m.put(1,"PHP");
m.put(2,"jQuery");
m.put(3,"JavaScript");
m.put(4,"Ruby");
m.put(5,"Java");
m.put(6,"AngularJS");
m.put(7,"ExpressJS");
System.out.println("TreeMap Elements...\n"+m);
System.out.println("\nSize of TreeMap: " + m.size());
}
}输出结果
TreeMap Elements...
{1=PHP, 2=jQuery, 3=JavaScript, 4=Ruby, 5=Java, 6=AngularJS, 7=ExpressJS}
Size of TreeMap: 7