Java CopyOnWriteArrayList removeIf()用法及代碼示例

CopyOnWriteArrayList的removeIf()方法從此CopyOnWriteArrayList中移除滿足指定條件的元素。

用法:

public boolean removeIf (Predicate<E> filter)

參數：此方法接受強製性參數過濾器，該過濾器是基於從該列表中刪除哪些元素的謂詞值。

返回值：如果CopyOnWriteArrayList更改，則此方法返回布爾值，例如true。否則，此方法返回false。

異常：如果指定的謂詞過濾器為null，則此方法將引發NullPointerException。

以下示例程序旨在說明CopyOnWriteArrayList類的removeIf()函數：

// Java Program to illustrate the CopyOnWriteArrayList 
// removeIf() method in Java 
  
import java.util.concurrent.CopyOnWriteArrayList; 
import java.util.*; 
  
public class GFG { 
    public static void main(String[] args) 
    { 
  
        // create object of CopyOnWriteArrayList 
        CopyOnWriteArrayList<Integer> ArrLis 
            = new CopyOnWriteArrayList<Integer>(); 
  
        // Add elements 
        ArrLis.add(2); 
        ArrLis.add(3); 
        ArrLis.add(4); 
        ArrLis.add(7); 
        ArrLis.add(6); 
        ArrLis.add(9); 
  
        // print CopyOnWriteArrayList 
        System.out.println("CopyOnWriteArrayList: "
                           + ArrLis); 
  
        // if a number in the List is 
        // divisible by 3, then remove it 
        ArrLis.removeIf(number -> number % 3 == 0); 
  
        // print updated CopyOnWriteArrayList 
        System.out.println("Updated CopyOnWriteArrayList: "
                           + ArrLis); 
    } 
}

輸出：

CopyOnWriteArrayList: [2, 3, 4, 7, 6, 9]
Updated CopyOnWriteArrayList: [2, 4, 7]

// Java Program to illustrate the CopyOnWriteArrayList 
// removeIf() method in Java 
  
import java.util.concurrent.CopyOnWriteArrayList; 
import java.util.*; 
  
public class GFG { 
    public static void main(String[] args) 
    { 
  
        // create object of CopyOnWriteArrayList 
        CopyOnWriteArrayList<String> ArrLis 
            = new CopyOnWriteArrayList<String>(); 
  
        // Add elements 
        ArrLis.add("GeeksforGeeks"); 
        ArrLis.add("GFG"); 
        ArrLis.add("Geeks"); 
        ArrLis.add("Gfg"); 
  
        // print CopyOnWriteArrayList 
        System.out.println("CopyOnWriteArrayList: "
                           + ArrLis); 
  
        try { 
  
            // This will throw NullPointerException 
            ArrLis.removeIf(null); 
        } 
        catch (Exception e) { 
            System.out.println(e); 
        } 
    } 
}

輸出：

CopyOnWriteArrayList: [GeeksforGeeks, GFG, Geeks, Gfg]
java.lang.NullPointerException

參考： https://docs.oracle.com/javase/9/docs/api/java/util/concurrent/CopyOnWriteArrayList.html#removeIf-java.util.function.Predicate-

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注：本文由純淨天空篩選整理自ProgrammerAnvesh大神的英文原創作品 CopyOnWriteArrayList removeIf() method in Java with Examples。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。