Void identifier in Golang

_(underscore) in Golang is called Blank Identifier . Identifier is a user-defined name of program elements used for identification purposes.

Void identifier in Golang

Golang has a special feature of defining and using unused variables using Blank Identifier. Unused variables are those variables that are defined by the user during the program but he never uses them. These variables make the program almost unreadable. As you know, Golang is a more concise and readable programming language so it does not allow the programmer to define an unused variable. If you do so, the compiler will give you an error.

The real use of Blank Identifier comes when a function returns multiple values, but we only need a few values ​​and need to get rid of the extra ones. It basically tells the compiler that this variable is not needed and ignores it without any error. It hides the values ​​of the variable and makes the program readable. So whenever you assign a value to Blank Identifier, it will not be used.

Example 1: In the program below, the function mul_div returns two values ​​and we store both values ​​in mul and div identifiers . But in the entire program, we are using only one variable i.e. mul . So, the compiler will throw an error that div is declared and not used.

// Chương trình Go hiện trình biên dịch
// báo lỗi nếu một biến
// được khai báo nhưng không được sử dụng

package main

import "fmt"

// Hàm chính
func main() {

	// gọi hàm này
	// hàm trả về hai giá trị được gán
	// cho định danh mul và div
	mul, div := mul_div(105, 7)

	// chỉ dùng biến mul
	// trình biên dịch sẽ báo lỗi
	fmt.Println("105 x 7 = ", mul)
}

// hàm trả về hai 
// giá trị của kiểu integer 
func mul_div(n1 int, n2 int) (int, int) {

	// trả về các giá trị này
	return n1 * n2, n1 / n2
}

Result:

./prog.go:15:7: div được khai báo nhưng không được dùng

Example 2: Use the Blank identifier to fix the above program. Instead of the div identifier, just use _ (underscore) . It allows the compiler to ignore the declaration error and not use it for that particular variable.

// Chương trình Go dùng định danh trống

package main

import "fmt"

// Hàm chính
func main() {

	// gọi hàm này
	// hàm trả về hai giá trị
	// được gán cho định danh mul và trống
	mul, _ := mul_div(105, 7)

	// chỉ dùng biến mul
	fmt.Println("105 x 7 = ", mul)
}

// hàm trả về hai giá trị
// của kiểu integer 
func mul_div(n1 int, n2 int) (int, int) {

	// trả về giá trị này
	return n1 * n2, n1 / n2
}

Result:

105 x 7 =  735

Important points to remember:

  • You can use multiple blank identifiers in the same program. So you can say that a Golang program can have multiple variables using the same identifier name blank.
  • There are many cases where a value is required just to complete the syntax even though the values ​​are known to not be used anywhere in the program. Like a function that returns multiple values. Most of such cases use the blank identifier.
  • You can use any value of any type with Blank Identifier.
Sign up and earn $1000 a day ⋙

Leave a Comment

Named return parameters in Golang

Named return parameters in Golang

In Golang, named return parameters are often referred to as named parameters. Golang allows naming the return parameters or results of functions in the function signature or definition.

Keywords in Go

Keywords in Go

Keyword - Keywords are words in a language that are used for some internal processes or represent some predefined actions. Here is what you need to know about keywords in Golang.

Data types in Golang

Data types in Golang

Data types specify what type of data a valid Go variable can hold. In the Go language, types are divided into four categories as follows:

Function arguments in Golang

Function arguments in Golang

Go supports two main ways to pass arguments: Pass by Value and Pass by Reference. Go uses pass by value by default.

Function returning multiple values ​​in Golang

Function returning multiple values ​​in Golang

In Go language, you are allowed to return multiple values ​​from a function, using the return statement. In other words, in a function, a return statement can return multiple values.

Switch Statement in Go

Switch Statement in Go

Golang like most other programming languages ​​has switch statement. Here is how to use switch statement in Golang.

Cases to know when using selection statements in Golang

Cases to know when using selection statements in Golang

In this article, we will learn how to use default case to avoid deadlock. But first, we will learn what is deadlock case when using select command in Golang?

Anonymous structures and fields in Golang

Anonymous structures and fields in Golang

Anonymous structs in Golang are temporary structures with no names used for one-time purposes, while anonymous fields allow embedding of unnamed fields.

How to use Rune in Golang

How to use Rune in Golang

What is Rune in Golang? How to use Rune in Golang? This article will give you the answer.

How to use operators in Golang

How to use operators in Golang

Operators allow us to perform different types of operations on operands. In Go language, operators can be classified based on their different functions.

How to create basic program in Golang

How to create basic program in Golang

Hello, World! is the first basic program in any programming language. You can write this first program in Golang by following the steps below.

How to Install Go on Windows

How to Install Go on Windows

Golang can be easily installed on Windows. Here is a step-by-step guide to install Golang on Windows.

Methods with the same name in Golang

Methods with the same name in Golang

Golang allows creating two or more methods with the same name in the same package, but the receivers of these methods must be of different types.

Functions in Go

Functions in Go

In Go, functions are blocks of code that perform specific tasks, which can be reused throughout the program to save memory, improve readability, and save time.

How to change units of measurement on Apple Maps

How to change units of measurement on Apple Maps

Apple Maps application supports you to change the measurement unit between km, mile, and miles, depending on each person's needs and usage habits.

7 ChatGPT and AI Apps for Free Travel Planning

7 ChatGPT and AI Apps for Free Travel Planning

These free travel planning apps use AI and Machine Learning tools like ChatGPT to prepare your itinerary in seconds.

How to use Gemini from Google Chrome address bar

How to use Gemini from Google Chrome address bar

Google is integrating AI features into the Google Chrome browser, most recently using Gemini from the Google Chrome address bar.

4 Ways to Change User Account Type in Windows

4 Ways to Change User Account Type in Windows

In addition to creating multiple users, Windows 10 also lets you limit what others can do on a shared PC, by providing multiple types of accounts, namely standard user accounts and admin accounts.

10 useful shortcuts to increase productivity on Microsoft Edge

10 useful shortcuts to increase productivity on Microsoft Edge

Keyboard shortcuts are a great productivity tool, especially for those whose jobs involve a lot of typing.

Serious bug forces Google to pause AI feature that creates images with text

Serious bug forces Google to pause AI feature that creates images with text

Google has announced that it is suspending the feature of generating images of people from text of its Gemini AI model due to a serious historical error.

How to Use Copilot in PowerPoint

How to Use Copilot in PowerPoint

Copilot will help you add creative ideas to your PowerPoint content slides, or fix the bad content in your presentation slides.

How to delete Google Gemini conversation

How to delete Google Gemini conversation

Instead of deleting your entire Google Gemini history, you can choose to delete the conversations you want. This article will guide you through deleting your Google Gemini conversations.

How to Downgrade from iOS 16 Beta 1 to iOS 15

How to Downgrade from iOS 16 Beta 1 to iOS 15

In this article, WebTech360 will guide you how to downgrade from iOS 16 Beta to iOS 15.

How to fix #SPILL! error in Microsoft Excel

How to fix #SPILL! error in Microsoft Excel

The #SPILL! error in Excel is quite common and it is quite simple to fix. Here is how to fix the #SPILL! error easily in Excel.

The best apps to monitor children using phones

The best apps to monitor children using phones

Here's a list of the best parental control apps, to help you compare the different options available.

How to pin media controls to Chromebook Shelf

How to pin media controls to Chromebook Shelf

To use this feature, your Chromebook must be running Chrome OS 89 or later.

How to Stop Sharing Safari Web History Across Multiple Devices

How to Stop Sharing Safari Web History Across Multiple Devices

Safari browser shares web history with other Apple devices that share the same iCloud account. Many people concerned about privacy can refer to the article to stop sharing.

How to Resize Images Properly in Photoshop

How to Resize Images Properly in Photoshop

Many people used to find resizing images very annoying until they learned about Photoshop's simple channel-based protection method.

How to avoid the most common Valentines Day scams

How to avoid the most common Valentines Day scams

Valentine's Day is prime time for scammers. However, you can ensure your February 14th goes smoothly by avoiding these scams.