Different methods to add Java array elements

Several ways to add elements to Java arrays

In Java programming, we often need to add new elements to arrays. This article will introduce several common ways to add elements to Java arrays and provide corresponding code examples.

1. Using loop assignment

Using loop assignment is a common way to add elements to an array. This method creates a new array, copies the elements of the original array to the new array, and then adds the new elements to the end of the new array. The specific code example is as follows:

public static int[] addElementToArray(int[] arr, int element) {
    int[] newArr = new int[arr.length + 1];
    for (int i = 0; i < arr.length; i++) {
        newArr[i] = arr[i];
    }
    newArr[newArr.length - 1] = element;
    return newArr;
}

When using this method to add elements, you need to pass in the original array and the new element to be added as parameters, and return the new array.

2. Using the ArrayList class

The ArrayList class in Java provides a convenient way to add elements to an array. The ArrayList class can automatically resize the array, so we can directly add elements to the end of the array using its add() method. The code example is as follows:

import java.util.ArrayList;

public static void main(String[] args) {
    ArrayList<Integer> list = new ArrayList<>();
    list.add(1);
    list.add(2);
    list.add(3);
    System.out.println(list); // 输出 [1, 2, 3]
}

When using this method to add elements, you need to create an ArrayList object first, and then use the add() method to add elements.

3. Using the ArrayUtils class

The ArrayUtils class in the Apache Commons Lang library provides a simple way to add elements to an array. This class provides a method to extend a new array based on the original array and add new elements to the end of the new array. The specific code example is as follows:

import org.apache.commons.lang3.ArrayUtils;

public static void main(String[] args) {
    int[] arr = {1, 2, 3};
    int element = 4;
    int[] newArr = ArrayUtils.add(arr, element);
    System.out.println(Arrays.toString(newArr)); // 输出 [1, 2, 3, 4]
}

When using this method to add elements, you need to import the ArrayUtils class first, and pass the original array and the new element to be added as parameters to the add() method.

Summary:

This article introduces several common ways to add elements to Java arrays. Adding new elements to an array can be achieved using loop assignment, the ArrayList class, and the ArrayUtils class. Developers can choose the appropriate way to add elements based on actual needs to improve the efficiency and readability of the code.

Note: The sample code in this article is for demonstration purposes only. Please modify and optimize it according to the actual application.

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