Introduction

Go slices are a flexible and powerful data structure that provides a convenient way to work with dynamic arrays. In this guide, we'll explore what slices are, how they work, and provide sample code to demonstrate their usage.


What Are Slices?

A slice in Go is a lightweight data structure that represents a portion of an array. Unlike arrays, slices are dynamic in size, making them ideal for working with collections of data whose length may change during program execution.


Creating Slices

You can create a slice using the built-in make function or by slicing an existing array or slice. Here's an example using make:

package main
import "fmt"
func main() {
    // Create a slice with a length of 3 and a capacity of 5.
    mySlice := make([]int, 3, 5)
    fmt.Println("Slice:", mySlice)
    fmt.Println("Length:", len(mySlice))
    fmt.Println("Capacity:", cap(mySlice))
}

In this code, we create a slice mySlice with a length of 3 and a capacity of 5. The length is the number of elements in the slice, and the capacity is the maximum number of elements it can hold.


Modifying Slices

Slices are flexible and allow for easy modifications, such as appending elements or slicing. Here's an example of appending elements to a slice:

package main
import "fmt"
func main() {
    mySlice := make([]int, 3, 5)
    fmt.Println("Original Slice:", mySlice)
    // Append an element to the slice.
    mySlice = append(mySlice, 42)
    fmt.Println("Modified Slice:", mySlice)
}

In this code, we create a slice and then append an element to it using the append function.


Slicing Slices

Slicing allows you to create new slices from an existing one. It's done by specifying the start and end indices. Here's an example:

package main
import "fmt"
func main() {
    numbers := []int{1, 2, 3, 4, 5, 6, 7, 8, 9}
    slice1 := numbers[2:5] // Slice from index 2 to 4 (5-1).
    fmt.Println("Original Slice:", numbers)
    fmt.Println("Sliced Slice:", slice1)
}

In this code, we create a slice numbers and then create a new slice slice1 by slicing a portion of the original slice.


Further Resources

To dive deeper into Go slices, consider these resources: