Java 中的 ConcurrentSkipListMap clear()方法，带示例
原文:https://www . geeksforgeeks . org/concurrentskiplistmap-clear-method-in-Java-with-examples/
java . util . concurrentskiplistmap的 clear() 方法是 Java 中的一个内置函数，它删除了该映射中的所有映射。这意味着地图中的所有元素都被移除，并返回一个空地图。
语法:
public void clear()
参数:函数不接受任何参数。
返回值:该函数从此映射中移除所有映射。
下面的程序说明了上述方法:
程序 1:
// Java Program Demonstrate clear()
// method of ConcurrentSkipListMap
import java.util.concurrent.*;
class GFG {
public static void main(String[] args)
{
// Initializing the map
ConcurrentSkipListMap<Integer, Integer>
mpp = new ConcurrentSkipListMap<Integer,
Integer>();
// adding elements in map
for (int i = 1; i <= 5; i++)
mpp.put(i, i);
// print original map
System.out.println("map elements are: "
+ mpp);
mpp.clear();
// after clear() operation
System.out.println("after clear the map is: "
+ mpp);
}
}
输出:
map elements are: {1=1, 2=2, 3=3, 4=4, 5=5}
after clear the map is: {}
程序二:
// Java Program Demonstrate clear()
// method of ConcurrentSkipListMap
import java.util.concurrent.*;
class GFG {
public static void main(String[] args)
{
// Initializing the map
ConcurrentSkipListMap<Integer, Integer>
mpp = new ConcurrentSkipListMap<Integer,
Integer>();
// adding elements in map
for (int i = 1; i <= 10; i++)
mpp.put(i, i);
// print original map
System.out.println("map elements are: "
+ mpp);
mpp.clear();
// after clear() operation
System.out.println("after clear the map is: "
+ mpp);
}
}
输出:
map elements are: {1=1, 2=2, 3=3, 4=4, 5=5, 6=6, 7=7, 8=8, 9=9, 10=10}
after clear the map is: {}
参考:https://docs . Oracle . com/javase/8/docs/API/Java/util/concurrentskiplistmap . html # clear–
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