How to Use Arrays in Go?

This blog describes How to Use Arrays in Go.

Arrays in Go are fixed-size collections of elements of the same type. The size of an array is part of its type, so they cannot be resized after they are declared. The following section describes how todeclare and access arrays.

Declaration

You can declare an array using the following syntax.

var arrayName [size]dataType

For example.

var numbers [5]int // Array of 5 integers

Initialization

Arrays can be initialized when declared or later using array literals.

var numbers = [5]int{1, 2, 3, 4, 5} // Initializing array when declared

// Later initialization
var numbers [5]int
numbers = [5]int{1, 2, 3, 4, 5}

Accessing Elements

You can access individual elements of an array using square brackets [] notation with the index of the element.

for i := 0; i < len(numbers); i++ {
    fmt.Println(numbers[i])
}

Alternatively, you can use a range-based for loop.

for index, value := range numbers {
    fmt.Printf("numbers[%d] = %d\n", index, value)
}

Arrays are Value Types

In Go, when you assign one array to another, a copy of the original array is created.

a := [3]int{1, 2, 3}
b := a // b is a copy of a

Array Size

The size of an array is part of its type. Therefore, two arrays with different sizes are considered different types.

var arr1 [3]int
var arr2 [5]int

Arrays in Functions

Arrays can be passed to functions as arguments. However, since they are value types, passing a large array to a function can be inefficient. In practice, slices are often used instead for passing around collections of data. For example.

package main

import "fmt"

// Function to modify slice elements
func modifySlice(slice []int) {
    slice[0] = 100
    slice[1] = 200
    slice[2] = 300
}

// Function to print slice elements
func printSlice(slice []int) {
    for _, value := range slice {
        fmt.Println(value)
    }
}

func main() {
    // Declare and initialize a slice
    numbers := []int{1, 2, 3}

    fmt.Println("Before modification:")
    printSlice(numbers) // Print original slice

    fmt.Println("After modification:")
    modifySlice(numbers) // Modify slice
    printSlice(numbers) // Print modified slice
}

Output

**Passing Arrays as Argument to a Function**

This covers the basics of arrays in Go. They provide a simple way to work with collections of data with a fixed size. However, slices, a more flexible data structure and they are more commonly used in Go for dynamic collections.

Declaration

Initialization

Accessing Elements

Arrays are Value Types

Array Size

Arrays in Functions

Further Reading

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Declaration

Initialization

Accessing Elements

Arrays are Value Types

Array Size

Arrays in Functions

Further Reading

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