Working with Arrays

Understanding Arrays in Go

Arrays in Go are a core collection type that lets you store a fixed-size sequence of elements of the same type. You use arrays when you know exactly how many items you need to store, and you want them grouped together in a single variable.

Declaring Arrays

To declare an array, specify its length and the type of its elements. For example, to declare an array of five integers:

var numbers [5]int

This creates an array named numbers that can hold exactly five integers. All elements are automatically set to the zero value for their type (0 for int).

Initializing Arrays

You can initialize an array at the time of declaration by providing values in curly braces:

var primes = [4]int{2, 3, 5, 7}

You can also let Go count the number of elements for you by using ... instead of a specific length:

odds := [...]int{1, 3, 5, 7, 9}

Accessing Array Elements

Access elements in an array using zero-based indexing. The first element is at index 0, the second at 1, and so on:

fmt.Println(primes[2]) // Prints: 5

You can also assign new values to specific elements:

numbers[0] = 42

Key Points

• Arrays have a fixed length and cannot be resized;
• All elements must be of the same type;
• Indexing starts at zero;
• Arrays are value types, meaning assignments copy the entire array.

Arrays are fundamental to data organization in Go and serve as the foundation for more advanced collections like slices.