Arrays in Go

In this tutorial, we will learn about arrays in Go. We will cover the basics of declaring and using arrays, including accessing and modifying elements.

What is an Array

An array is a collection of elements of the same type stored in contiguous memory locations. It allows you to store multiple items under a single name and access them using an index.

An array of integers

Syntax

The syntax to declare an array in Go is:

var arrayName [arraySize]type

where the collection can be an array, slice, map, or string.

Working with Arrays

We will learn how to declare, initialize, access, and modify arrays in Go.


Example 1: Declaring and Initializing an Array

We have already seen the syntax to declare an array. For example, the following statement declares an integer array arr of size 5.

var arr = [5]int
Now, by default the elements in integer array would be initialized to 0. Or you can specify the elements after the type in the curly braces as shown below. 
var arr = [5]int{1, 2, 3, 4, 5}

Let us go through an example, where we

For example,

  1. Declare an integer array named arr with 5 elements.
  2. Initialize the array with values {1, 2, 3, 4, 5}.
  3. Print all the elements of the array using range for loop.

Go Program

package main
import "fmt"
func main() {
    var arr = [5]int{1, 2, 3, 4, 5}
    for _, num := range arr {
        fmt.Print(num, " ")
    }
}

Output

1 2 3 4 5

Example 2: Accessing Array Elements

  1. Declare an integer array named arr with 5 elements.
  2. Initialize the array with values {10, 20, 30, 40, 50}.
  3. Access and print the third element of the array.

Go Program

package main
import "fmt"
func main() {
    var arr = [5]int{10, 20, 30, 40, 50}
    fmt.Println("The third element is:", arr[2])
}

Output

The third element is: 30

Example 3: Modifying Array Elements

  1. Declare an integer array named arr with 5 elements.
  2. Initialize the array with values {5, 10, 15, 20, 25}.
  3. Modify the second element of the array to 50.
  4. Print all the elements of the array.

Go Program

package main
import "fmt"
func main() {
    var arr = [5]int{5, 10, 15, 20, 25}
    arr[1] = 50
    for _, num := range arr {
        fmt.Print(num, " ")
    }
}

Output

5 50 15 20 25