Use java's ArrayList.get() function to get the element at the specified index position of ArrayList

Use java's ArrayList.get() function to obtain the element at the specified index position of ArrayList

ArrayList is a commonly used dynamic array in Java and can store any type of object. By indexing the position, we can easily get the element at the specified position in the ArrayList. In this article, we will explore how to use the get() function of ArrayList to achieve this functionality.

Suppose we have an ArrayList that stores the names of some students. We want to be able to get a student's name by index location. First, we need to create an ArrayList object and add some elements, and then use the get() function to get the element at the specified position.

The following is a sample code:

import java.util.ArrayList;

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

        // 添加一些学生姓名
        studentNames.add("张三");
        studentNames.add("李四");
        studentNames.add("王五");
        studentNames.add("赵六");

        // 获取指定索引位置的学生姓名
        String studentName = studentNames.get(2);

        // 打印输出结果
        System.out.println("第二个学生的姓名是：" + studentName);
    }
}

In the above code, we first create an ArrayList object and add four student names to it using the add() function. Then, we use the get() function to get the student name at index position 2 and store the result in a string variable. Finally, we use the System.out.println() function to print the output results.

Executing the above code will output the following results:

第二个学生的姓名是：王五

As you can see, the student name at the specified index position was successfully obtained through the get() function. It should be noted that the index of ArrayList starts counting from 0, so index position 2 corresponds to the third element.

In addition to getting a single element, we can also use the get() function to get the entire ArrayList. For example, get the names of all students through loop traversal:

// 遍历ArrayList并打印所有学生姓名
for (int i = 0; i < studentNames.size(); i++) {
    System.out.println("第" + (i + 1) + "个学生的姓名是：" + studentNames.get(i));
}

With the above code, we can print out the names of all students in the ArrayList one by one.

Summary: Use the get() function to easily obtain the element at the specified index position in the ArrayList. In practical applications, we can perform various data operations and processing based on this feature. It should be noted that before using the get() function to obtain an element, make sure that the element at the corresponding index position already exists in the ArrayList, otherwise an IndexOutOfBoundsException exception will be thrown.

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