The Go Language – Exploring Functions – part 6 – 6.2 – discussing Variadic Functions

Hi All,

Greetings for the day !!!

We are continuing exploring Go language

In following previous articles we explored introduction to Go, wrote our first Go program, went through basic data types in Go, exploring strings in Go, exploring Constants and started exploring functions.

• The Go Language – Introduction Part 1
• The Go Language – Writing first program
• The Go Language – basic data types – Part 3
• The Go Language – exploring Strings – Part 4.1
• The Go Language – exploring Strings – Part 4.2
• The Go Language – Exploring Constants – part 5
• The Go Language – Exploring Functions – part 6 – 6.1

In this article we will continue to explore functions – we will discuss “Variadic functions“

Take away from this article

• What are Variadic Functions
• Demonstration / sample code for Variadic functions
• How Variadic Function works
• Use case for Variadic Functions

Variadic Functions

• Function is variadic function if it is called with varying number of arguments
• Variadic functions accepts a variable number of arguments
• Example – we have fmt.Println function (fmt package)
  • fmt.Println() requires any number of arguments as shown in below fig
  • As in below fig, we are using two variants of fmt.Println() – one is with one argument and second call is with two arguments

• Declaration of Variadic functions – To declare Variadic function we need last parameter preceded by an ellipsis, “…” – this means function may get called with any number of arguments
• Example :Lets have a function whose last parameter is variadic as in below code, as in below code – we have param2 is variadic

func Variadic_functions(param1 int, param2 ...int){
     //Variadic functions implementation goes here
}

//main package
package main

//importing - required packages
import (
	"fmt" // package for println()
) //import

//main func - Go program entry
func main() {
	fmt.Println("Variadic  function demonstration")

	//Calling Variadic_function_ReturnStrings with 1 argument
	Variadic_function_ReturnStrings("HELLO")
	//Calling Variadic_function_ReturnStrings with 2 arguments
	Variadic_function_ReturnStrings("WE", "RICH")
	//Calling Variadic_function_ReturnStrings with 3 arguments
	Variadic_function_ReturnStrings("LIFE", "IS", "BEAUTIFUL")

} //main func

//simple variadic function demo
//function have simple one variadic argument
//while calling, we will pass multiple arguments

func Variadic_function_ReturnStrings(variadicParam ...string) {
	//Variadic functions implementation goes here
	fmt.Println(variadicParam)
} //Variadic_function_JoinStrings

Output of the program will be

Variadic  function demonstration
[HELLO]
[WE RICH]
[LIFE IS BEAUTIFUL]

• How variadic function works
  • Variadic functions converts variadic argument to a slice of the type of variable parameter
  • This means we can travel also through the range of values of variadic parameter

//main package
package main

//importing - required packages
import (
	"fmt" // package for println()
) //import

//main func - Go program entry
func main() {
	fmt.Println("Variadic  function demonstration")

	//Calling Variadic_function_ReturnStrings with 1 argument
	//Variadic_function_ReturnStrings("HELLO")
	//Calling Variadic_function_ReturnStrings with 2 arguments
	//Variadic_function_ReturnStrings("WE", "RICH")
	//Calling Variadic_function_ReturnStrings with 3 arguments
	//Variadic_function_ReturnStrings("LIFE", "IS", "BEAUTIFUL")

	//Calling Variadic_function_TravelStrings with 1 argument
	Variadic_function_TravelStrings("HELLO")
	//Calling Variadic_function_TravelStrings with 2 arguments
	Variadic_function_TravelStrings("WE", "RICH")
	//Calling Variadic_function_TravelStrings with 3 arguments
	Variadic_function_TravelStrings("LIFE", "IS", "BEAUTIFUL")

} //main func

//simple variadic function demo
//function have simple one variadic argument
//while calling, we will pass multiple arguments
func Variadic_function_ReturnStrings(variadicParam ...string) {
	//Variadic functions implementation goes here
	fmt.Println(variadicParam)
} //Variadic_function_ReturnStrings

//simple variadic function demo
//function have simple one variadic argument
//while calling, we will pass multiple arguments and will traverse through those number of arguments passed
func Variadic_function_TravelStrings(variadicParam ...string) {
	//Variadic functions implementation goes here

	//looping throgh the variadic parameter
	for _, str := range variadicParam {
		fmt.Println(str)
	} //for

} //Variadic_function_TravelStrings

Output of the above program will be

Variadic  function demonstration
HELLO
WE
RICH
LIFE
IS
BEAUTIFUL

• Variadic functions are mostly used for strings formatting
• Variadic functions are also used in scenario where we don’t know the number of parameters in advance

Thanks for reading!!! Please feel free to discuss in case any questions / suggestions / thoughts !!!

HAVE A GREAT TIME AHEAD !!! LIFE IS BEAUTIFUL 🙂