Java 中 CopyOnWriteArrayList 的 contains() 方法
CopyOnWriteArrayList 類的 contains() 方法用於獲取指定元素。如果元素在列表中,則返回 TRUE,否則返回 FALSE。
語法如下
boolean contains(Object ob)
此處,ob 是要檢查是否存在性的元素。要操作 CopyOnWriteArrayList 類,你需要匯入以下包
import java.util.concurrent.CopyOnWriteArrayList;
以下是使用 Java 中的 CopyOnWriteArrayList 類 contains() 方法的示例
示例
import java.util.concurrent.CopyOnWriteArrayList; public class Demo { public static void main(String[] args) { CopyOnWriteArrayList<Integer> arrList = new CopyOnWriteArrayList<Integer>(); arrList.add(100); arrList.add(250); arrList.add(400); arrList.add(500); arrList.add(650); arrList.add(700); arrList.add(800); System.out.println("CopyOnWriteArrayList Elements = " + arrList); System.out.println("The element at 2nd position = " + arrList.get(1)); System.out.println("Does the element exist in the List? = " + arrList.contains(400)); } }
輸出
CopyOnWriteArrayList Elements = [100, 250, 400, 500, 650, 700, 800] The element at 2nd position = 250 Does the element exist in the List? = true
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