Remove elements from ArrayList using java's ArrayList.remove() function

Use java's ArrayList.remove() function to remove elements from ArrayList

In Java, ArrayList is a commonly used collection class used to store and operate a set of elements. The ArrayList class provides many methods to add, delete, modify, and query elements in the collection. One of the more frequently used methods is remove(), which can remove elements from an ArrayList.

The remove() method of ArrayList has two overloaded forms, one is to delete elements based on the index position, and the other is to delete elements based on the element value. Below we will introduce the use of these two methods one by one.

1. Delete elements based on index position
   The remove() method of ArrayList can delete elements based on their index position. The following is a sample code:

import java.util.ArrayList;

public class ArrayListRemoveExample {
    public static void main(String[] args) {
        // 创建一个ArrayList对象
        ArrayList fruits = new ArrayList<>();

        // 添加一些元素到ArrayList
        fruits.add("apple");
        fruits.add("banana");
        fruits.add("orange");
        fruits.add("grape");

        System.out.println("原始的ArrayList: " + fruits);

        // 移除索引为2的元素
        fruits.remove(2);

        System.out.println("删除索引为2的元素后的ArrayList: " + fruits);
    }
}

Running the above code, we can get the following output:

Original ArrayList: [apple, banana, orange, grape]
Delete index ArrayList after the element of 2: [apple, banana, grape]

As can be seen from the output result, after the elements are deleted according to the index position through the remove() method, the elements in the ArrayList are reordered.

2. Delete elements based on element value
   In addition to based on index position, ArrayList's remove() method can also delete specified elements based on element value. The following is a sample code:

import java.util.ArrayList;

public class ArrayListRemoveExample {
    public static void main(String[] args) {
        // 创建一个ArrayList对象
        ArrayList fruits = new ArrayList<>();

        // 添加一些元素到ArrayList
        fruits.add("apple");
        fruits.add("banana");
        fruits.add("orange");
        fruits.add("grape");

        System.out.println("原始的ArrayList: " + fruits);

        // 移除元素值为"banana"的元素
        fruits.remove("banana");

        System.out.println("删除元素值为'banana'的元素后的ArrayList: " + fruits);
    }
}

Running the above code, we can get the following output:

Original ArrayList: [apple, banana, orange, grape]
Remove elements ArrayList after the element whose value is 'banana': [apple, orange, grape]

As can be seen from the output result, after the elements are deleted according to the element value through the remove() method, the order of the elements in the ArrayList is no longer the same. will change.

It should be noted that if there are multiple identical element values ​​in the ArrayList, the remove() method will only delete the first element that appears.

To sum up, using the remove() method of ArrayList can easily remove elements in ArrayList. We can delete specified elements based on index position or element value. By mastering the usage of the remove() method, we can operate the data in the ArrayList collection more flexibly.

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