Core Java

Get the First and the Last Elements From an Array in Java

In this article, we will explore different approaches to getting the first and last elements from an array in Java.

1. What are arrays in Java?

In Java, arrays are a fundamental data structure used to store multiple values of the same type in a single variable. Arrays are fixed in size, and their elements are accessed using an index. The index of the first element is 0, and the index of the last element is the array’s length minus one. Here’s a simple example of an array declaration and initialization in Java:

int[] numbers = {10, 20, 30, 40, 50};

1.1 Benefits and Use Cases of Arrays

  • Efficiency: Arrays allow for efficient data access and manipulation due to constant-time complexity (O(1)) for accessing elements by index.
  • Memory Management: Arrays provide a contiguous block of memory which can be beneficial for performance due to spatial locality.
  • Simplicity: Arrays have a simple structure and are easy to use and understand for basic data storage needs.
  • Static Size: Arrays have a fixed size, which can help prevent memory leaks by limiting the number of elements.
  • Use Cases:
    • Storing a list of items such as numbers, strings, or objects.
    • Implementing other data structures like stacks, queues, and matrices.
    • Buffering data for input/output operations.
    • Temporary storage for sorting and searching algorithms.
    • Representing multi-dimensional data, such as 2D arrays for matrices or game boards.

2. Obtaining the First and the Last Elements

To get the first and the last elements of an array in Java, you can use the following approach:

package com.jcg.example;

public class Main {
    public static void main(String[] args) {
        int[] numbers = {10, 20, 30, 40, 50};
        
        if (numbers.length > 0) {
            int firstElement = numbers[0];
            int lastElement = numbers[numbers.length - 1];
            
            System.out.println("First Element: " + firstElement);
            System.out.println("Last Element: " + lastElement);
        } else {
            System.out.println("The array is empty.");
        }
    }
}

In the above code:

  • numbers.length > 0: Checks if the array is not empty.
  • numbers[0]: Accesses the first element of the array.
  • numbers[numbers.length - 1]: Accesses the last element of the array.

The code returns the following output:

First Element: 10
Last Element: 50

3. What if the Array Is Empty?

It’s important to handle cases where the array might be empty to avoid errors. In the example above, we checked if the array’s length was greater than 0 before attempting to access its elements. If the array is empty, we print a message indicating that the array is empty.

package com.jcg.example;

public class Main {
    public static void main(String[] args) {
        int[] numbers = {}; // An empty array
        
        if (numbers.length > 0) {
            int firstElement = numbers[0];
            int lastElement = numbers[numbers.length - 1];
            
            System.out.println("First Element: " + firstElement);
            System.out.println("Last Element: " + lastElement);
        } else {
            System.out.println("The array is empty.");
        }
    }
}

4. Conclusion

In Java, obtaining the first and last elements of an array is straightforward. By checking if the array is not empty, you can safely access these elements using their respective indices. This basic operation is a useful technique for working with arrays in Java.

Yatin Batra

An experience full-stack engineer well versed with Core Java, Spring/Springboot, MVC, Security, AOP, Frontend (Angular & React), and cloud technologies (such as AWS, GCP, Jenkins, Docker, K8).
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