Go by Example: Variadic Functions

Variadic functions can be called with any number of trailing arguments. For example, fmt.Println is a common variadic function.

package main
import "fmt"

Here’s a function that will take an arbitrary number of ints as arguments.

func sum(nums ...int) {
	fmt.Print(nums, " ")
	total := 0
	for _, num := range nums {
		total += num
	}
	fmt.Println(total)
}
func main() {

Variadic functions can be called in the usual way with individual arguments.

	sum(1, 2)
	sum(1, 2, 3)

If you already have multiple args in a slice, apply them to a variadic function using func(slice...) like this.

	nums := []int{1, 2, 3, 4}
	sum(nums...)
}
$ go run variadic-functions.go 
[1 2] 3
[1 2 3] 6
[1 2 3 4] 10

Another key aspect of functions in Go is their ability to form closures, which we’ll look at next.

Previous example: Multiple Return Values.

Next example: Closures.