从 Java 中的 TreeMap 中移除所有值
使用 clear() 方法从 TreeMap 中移除所有值。
我们首先创建一个 TreeMap −
TreeMap<Integer,String> m = new TreeMap<Integer,String>();
向 TreeMap 中添加一些元素 −
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");
现在我们移除所有值 −
m.clear();
以下是从 TreeMap 中移除所有值的示例 −
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...");
Collection res = m.values();
Iterator i = res.iterator();
while (i.hasNext()){
System.out.println(i.next());
}
System.out.println("TreeMap size = "+m.size());
m.clear();
System.out.println("
TreeMap after removing all elements = "+m);
System.out.println("Size of TreeMap now = "+m.size());
}
}输出
TreeMap Elements...
PHP
jQuery
JavaScript
Ruby
Java
AngularJS
ExpressJS
TreeMap size = 7
TreeMap after removing all elements = {}
Size of TreeMap now = 0
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