Arrays
Java Arrays
As an alternative to declaring distinct variables for each value, arrays can hold many values in a single variable.
Use square brackets to define the variable type in order to declare an array:
String[] cars;
Now that we have a variable specified, it may hold an array of strings. You can add values to it by putting them inside curly braces as a list separated by commas:
String[] cars = {"Volvo", "BMW", "Ford", "Mazda"};
You could write: in order to generate an array of integers.
int[] myNum = {10, 20, 30, 40};
Access the Elements of an Array
The index number of an array element can be used to access it.
In cars, this statement retrieves the value of the first element:
Example
String[] cars = {"Volvo", "BMW", "Ford", "Mazda"};
System.out.println(cars[0]);
// Outputs Volvo
Recall that array indexes begin at 0: The first element is [0]. The second element is [1], and so on.
Change an Array Element
To modify an individual element’s value, consult 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
Use the length property to determine an array’s element count:
Example
String[] cars = {"Volvo", "BMW", "Ford", "Mazda"};
System.out.println(cars.length);
// Outputs 4
