Sort a slice in Ascending order

sort.Ints package of going can be used to sort a full slice or a part of the slice. It is going to sort the string into Ascending order.

Below is the signature of the method

https://pkg.go.dev/sort#Ints

func Ints(x []int)

It takes a slice ‘x’ as an argument and sorts the slice ‘x’ in place.

Below is the program for the same

package main

import (
	"fmt"
	"sort"
)

func main() {

	nums := []int{3, 4, 2, 1}
	fmt.Printf("Before: %v", nums)
	sort.Ints(nums)
	fmt.Printf("\nAfter: %v", nums)
}

Output

Before: [3 4 2 1]
After: [1 2 3 4]

Sort a slice in Descending order

To sort a slice in descending order we will use Slice method of sort pacakge

https://pkg.go.dev/sort#Slice

Below is the signature of the method

func Slice(x any, less func(i, j int) bool)

So this function takes two arguments

• x any – any is nothing here but an empty interface https://pkg.go.dev/builtin#any

• less func(i, j int) – This function is nothing but a comparator function

We can use this comparator function to decide the descending order of the elements in the slice. Below is an example

package main

import (
	"fmt"
	"sort"
)

func main() {

	nums := []int{3, 4, 2, 1}
	fmt.Printf("Before: %v", nums)
	sort.Slice(nums, func(i, j int) bool {
		return nums[i] > nums[j]
	})
	fmt.Printf("\nAfter: %v", nums)
}

Output

Before: [3 4 2 1]
After: [4 3 2 1]

As a matter of fact, you can use sort.Slice method to also sort a slice in descending order. Below is an example

package main

import (
	"fmt"
	"sort"
)

func main() {

	nums := []int{3, 4, 2, 1}
	fmt.Printf("Before: %v", nums)
	sort.Slice(nums, func(i, j int) bool {
		return nums[i] < nums[j]
	})
	fmt.Printf("\nAfter: %v", nums)
}

Output

Before: [3 4 2 1]
After: [1 2 3 4]

Note: Check out our Golang Advanced Tutorial. The tutorials in this series are elaborative and we have tried to cover all concepts with examples. This tutorial is for those who are looking to gain expertise and a solid understanding of golang - Golang Advance Tutorial

Also if you are interested in understanding how all design patterns can be implemented in Golang. If yes, then this post is for you -

All Design Patterns Golang

Note: Check out our system design tutorial series System Design Questions