Apex Array Basics (Declaration, Initialization, Accessing Elements)

Alright, let’s start with the nuts and bolts. In Apex, arrays are actually just a special kind of list. Think of them as boxes where you can line up similar items - strings, numbers, objects - all in one neat row.

Declaring and Initializing Arrays

There are a couple of ways to create arrays (aka List in Apex). Here's how:

// Empty array of Strings
String[] names = new String[]{};
System.debug(names); // Outputs: ()

// Array with initial values
String[] fruits = new String[]{'Apple', 'Banana', 'Cherry'};
System.debug(fruits); // Outputs: (Apple, Banana, Cherry)

// Integer array with initial values
Integer[] numbers = new Integer[]{1, 2, 3, 4, 5};
System.debug(numbers);

// Array with fixed size (elements default to null)
Integer[] fixedSizeArray = new Integer[4];
System.debug(fixedSizeArray); // Outputs: (null, null, null, null)

In Apex, you can use either the Type[] name syntax or the List<Type> name syntax. They’re interchangeable in most cases.

Accessing Elements

Once you've got data in your array, accessing it is a breeze. Just use the index, starting from zero:

System.debug(fruits[0]); // Apple
System.debug(fruits[2]); // Cherry

Need to update something?

fruits[1] = 'Blueberry';
System.debug(fruits); // (Apple, Blueberry, Cherry)

Just remember - if you try to access an index that doesn’t exist, Apex will throw an IndexOutOfBoundsException. Ouch.