DEV Community

Cover image for Create a slice with make

Posted on

Create a slice with make

In the Go programming language you can create arrays: collections.

You can create slices with the built-in make() function; you can create dynamically-sized arrays this way.

Remember that the usual array has a fixed size, that you would define in one of these two ways:

var a [10]int
var a = []int64{ 1,2,3,4 }

What if you want an array that contains zeroes?

Make() in Go

The make function allocates a zeroed array and returns a slice that refers to that array. The syntax of the make() function is:

your_array := make([]type, length)

So if you'd have a program like this:

package main

import "fmt"

func main() {
    a := make([]int, 5)
    printSlice("a", a)


func printSlice(s string, x []int) {
    fmt.Printf("%s len=%d cap=%d %v\n",
        s, len(x), cap(x), x)

It would output the array (contains a lot of zeros, the make() function does this):

a len=5 cap=5 [0 0 0 0 0]

To change its size, change the second parameter

a := make([]int, 50)

Top comments (0)