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Arrays in Java

Arrays

An array is a collection of values with the same data type.

String[] animals = {"Giraffe", "Elephant", "Toucan"}; // Access an element via its index: System.out.println(animals[0]); // Prints: Giraffe // Change an element value: animals[1] = "Lion"; // Find number of elements in an array: System.out.println(animals.length); // Prints: 3 // Traverse array using for loop: for (int i = 0; i < animals.length; i++) { System.out.println(animals[i]); } /* Prints: Giraffe Lion Toucan */ // Traverse array using for-each loop for (int i: animals) { System.out.println(i); } /* Prints: Giraffe Lion Toucan */

2D Arrays

A 2D array is an array that stores arrays of the same data type.

// Declare a 2D array that stores char arrays char[][] letters = {{'A', 'a'}, {'B', 'x'}, {'C', 'c'}}; // Access an element via its index: System.out.println(letters[0][1]); // Prints: a // Change an element by accessing its index: letters[1][1] = "b"; // Iterate over 2D array in row-major order: for (int i = 0; i < letters.length; i++){ for (int j = 0; j < letters[0].length; j++){ System.out.print(letters[i][j]); } } // Prints: AaBbCc // Iterate over 2D array in column-major order: for (int i = 0; i < letters[0].length; i++){ for (int j = 0; j < letters.length; j++){ System.out.print(letters[j][i]); } } // Prints: ABCabc

Related Courses

Course

Java for Programmers

Intermediate