从 ArrayList 中删除元素 [英] Remove elements from ArrayList

问题描述

我必须从 ArrayList 中删除元素，但我还没有完成.我必须删除的元素也在 ArrayList 中可用.简而言之，我必须从另一个数组列表中删除一个数组列表.例如假设

I have to remove elements from ArrayList, but I have not gone through it. Elements which I have to remove are also available in ArrayList. In short, I have to remove one Array List from another Array List. e.g. Suppose

ArrayList<String> arr1= new ArrayList<String>();
ArrayList<String> arr2 = new ArrayList<String>();
arr1.add("1"); 
arr1.add("2"); 
arr1.add("3"); 

arr2.add("2"); 
arr2.add("4"); 

现在，我必须从 arr1 中删除 arr2 中的元素.所以，我的最终答案是 1 和 3.需要做什么?

Now, I have to remove elements which are in arr2 from arr1. So, that I have final answer as 1 and 3. What needs to be done?

推荐答案

阅读 Java 删除两个列表中的公共元素

使用下面的代码

List<String> resultArrayList = new ArrayList<String>(arr1);
resultArrayList.removeAll(arr2);

<小时>

或者可以通过

---

Or can be done by

arr1.removeAll(arr2)

<小时>

SO 评论后

---

After SO comments

我使用了以下代码

ArrayList<String> arr1= new ArrayList<String>();
        ArrayList<String> arr2 = new ArrayList<String>();
        arr1.add("1"); 
        arr1.add("2"); 
        arr1.add("3"); 

        arr2.add("2"); 
        arr2.add("4"); 

        System.out.println("Before removing---");
        System.out.println("Array1 : " + arr1);
        System.out.println("Array2 : " + arr2);
        System.out.println("Removing common ---");
        List<String> resultArrayList = new ArrayList<String>(arr1);
        resultArrayList.removeAll(arr2);                
        System.out.println(resultArrayList);

并获得输出为

Before removing---
Array1 : [1, 2, 3]
Array2 : [2, 4]
Removing common ---
[1, 3]

那么什么在你身边不起作用?

So what is not working at your side?

阅读更多关于如何从另一个List中删除一个List的重叠内容?

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