Java Arrays
Java Arrays
Arrays are used to store multiple values in a single variable, instead of declaring separate variables for each value.
To declare an array, define the variable type with square brackets:
String[] cars;
We have now declared a variable that holds an array of strings. To insert values to it, we can use an array literal - place the values in a comma-separated list, inside curly braces:
String[] cars = {"Volvo", "BMW", "Ford", "Mazda"};
To create an array of integers, you could write:
int[] myNum = {10, 20, 30, 40};
Access the Elements of an Array
You access an array element by referring to the index number.
This statement accesses the value of the first element in cars:
Example
String[] cars = {"Volvo", "BMW", "Ford", "Mazda"};
System.out.println(cars[0]);
// Outputs Volvo
Note: Array indexes start with 0: [0] is the first element. [1] is the second element, etc.
Change an Array Element
To change the value of a specific element, refer to the index number:
Example
cars[0] = "Opel";
Example
String[] cars = {"Volvo", "BMW", "Ford", "Mazda"};
cars[0] = "Opel";
System.out.println(cars[0]);
// Now outputs Opel instead of Volvo
Array Length
To find out how many elements an array has, use the length property:
Example
String[] cars = {"Volvo", "BMW", "Ford", "Mazda"};
System.out.println(cars.length);
// Outputs 4
