Slice operations in Go, classic and modern approaches

slices.go

package main

import (
	"fmt"
	"slices"
)

func main() {
	classic()
	modern()
}

func classic() {
	vec := []int{1, 2, 3, 4}

	fmt.Println("--- classic ---")

	// add
	vec = append(vec, 5)
	fmt.Println(vec)

	// remove the last item
	vec = vec[:len(vec)-1]
	fmt.Println(vec)

	// remove from the middle
	idx := 2
	vec = append(vec[:idx], vec[idx+1:]...)
	fmt.Println(vec)

	// append to the middle (insert)
	vec = append(vec[:idx+1], vec[idx:]...)
	vec[idx] = 3
	fmt.Println(vec)
}

func modern() {
	vec := []int{1, 2, 3, 4}

	fmt.Println("--- modern ---")

	// add
	vec = append(vec, 5)
	fmt.Println(vec)

	// remove the last item
	vec = slices.Delete(vec, len(vec)-1, len(vec))
	fmt.Println(vec)

	// remove from the middle
	idx := 2
	vec = slices.Delete(vec, idx, idx+1)
	fmt.Println(vec)

	// append to the middle (insert)
	vec = slices.Insert(vec, idx, 3)
	fmt.Println(vec)
}