Void identifier in Golang
_(underscore) in Golang is called Blank Identifier. Identifier is a user-defined name of program elements used for identification purposes.
How to use variables in Golang
In programming languages, identifiers are used for exactly what their name suggests. In other words, identifiers are user-defined names for program elements. In Go, identifiers can be variable names, function names, constants, statement labels, package names, or types. Here's what you need to know about using identifiers in Golang.
For example:
package main
import "fmt"
func main() {
var name = "Quantrimang.com"
}There are a total of three identifiers available in the above example:
- main : Package name
- main : Name of the function
- name : Name of the variable
Variable Definition Rules: There are some valid rules for defining valid Go variables. These rules need to be followed, otherwise we will get compilation errors.
- An identifier name must begin with a letter or an underscore(_). And it can contain the letters 'a-z' or 'A-Z' or the numbers 0-9 as well as the character '_'.
- The identifier name cannot begin with a digit.
- Identifier names are case sensitive.
- Keywords are not allowed as identifiers.
- There is no limit on the length of an identifier name, but an optimal length of 4 – 15 letters is recommended.
For example:
// Valid identifiers:
_geeks23
geeks
gek23sd
Geeks
geeKs
geeks_geeks
// Invalid identifiers:
212geeks
if
defaultNote:
In Go, there are a number of pre-declared identifiers available for constants, types, and functions. These names are not reserved, you are allowed to use them in declarations. Here is a list of pre-declared identifiers:
Cho hằng số:
true, false, iota, nil
Cho các kiểu:
int, int8, int16, int32, int64, uint,
uint8, uint16, uint32, uint64, uintptr,
float32, float64, complex128, complex64,
bool, byte, rune, string, error
Cho các hàm:
make, len, cap, new, append, copy, close,
delete, complex, real, imag, panic, recover- A variable represented by an underscore character (_) is called an empty identifier. It is used as an anonymous placeholder instead of a regular identifier and has special meaning in declarations, as an operand, and in assignments.
- A variable that is accessible from another package is called an exported identifier. Exported identifiers are those identifiers that satisfy the following conditions:
- The first character of the exported identifier name must be an uppercase Unicode letter.
- The identifier must be declared within a package block or as the name of a variable, function, type, or method within that package.
In the example below, file1.go contains an exported variable named ExportedVariable , which is accessible within the same file. It also imports the file2 package and accesses the exported variable AnotherExportedVariable from file2.go . By running go run file1.go , it will print the value of ExportedVariable (“Hello, World!”) from file1.go and the value of AnotherExportedVariable (“Greetings from file2!”) from file2.go . This demonstrates the concept of exported variables being accessible from another package in Go.
Example of file2:
//file2.go
package file2
// Exported variable
var AnotherExportedVariable = "Greetings from file2!"
Example of file1:
// file1.go
package main
import (
"fmt"
"github.com/yourusername/project/file2"
)
// Biến được xuất
var ExportedVariable = "Hello, World!"
func main() {
// Truy cập biến đã xuất trong cùng file
fmt.Println(ExportedVariable)
// Truy cập biến đã xuất từ gói khác
fmt.Println(file2.AnotherExportedVariable)
}
Result:
Hello, World!
Greetings from file2!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
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
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
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.
Variable Scope in Go
The scope of a variable in Golang determines which part of the program the variable is accessible to. In Go, all identifiers have a lexical scope that is determined at compile time.
Control Statements in Golang (if, if-else, Nested-if)
What conditional statements does Golang have? How to use conditional statements in Go programming? Let's find out together!
Short variable declaration operator in Go
The short variable declaration operator (:=) in Golang is used to create variables with a proper name and initial value. Here is what you need to know about the short variable declaration operator in Golang.
Defer Keyword in Golang
In Go, defer statements delay execution of a function or method or an anonymous method until the nearby functions return.
Methods in Golang
Methods in Golang are like functions but with one major difference: they have a receiver argument, which allows access to the properties of the receiver.
Main and init functions in Golang
Go language has two special purpose functions and those functions are main() and init(). Here are the things to know about using main() and init() functions in Golang.
Anonymous Functions in Golang
Anonymous functions in Go are very useful. Below is the syntax, usage and example of using anonymous functions in Golang.
The var keyword in Go
The var keyword in Golang is used to create variables of a specific type with a specific name and initial value. Initialization is optional at the time of declaring the variable using the var keyword in Golang
Nested Structure in Golang
Go language allows nested structures. A structure that is a field of another structure is called Nested Structure.
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