The go language package has 4 reference methods, which are: 1. Use the standard reference method to introduce, the code is like "import ("fmt")"; 2. Use the alias reference method, the code is like " import (F "fmt")"; 3. Use omission to introduce, the code is like "import (. "fmt")"; 4. Import by only executing the package init function, the code is like "import ("fmt"_ "strconv")".
Operating system for this tutorial: Windows 10 system, go1.20.1 version, Dell G3 computer
Case
1. Use the standard reference method to import
Import the system’s built-in fmt package in the standard form
package main //通过标准的形式导入系统内置的 fmt 包 import ( "fmt" ) func main() { fmt.Println("PHP中文网(www.php.cn)") fmt.Println("Golang Pakckage import") }
After the program is run, the console output is as follows:
PHP中文网(www.php.cn) Golang Pakckage import
us Using the standard method, the fmt package is introduced, and the functions in the package can be called directly using the form fmt. in the main function.
2. Use alias reference to introduce
Introduce the system’s built-in fmt package through alias reference
package main //通过别名引用方式引入系统内置的 fmt 包 import ( F "fmt" ) func main() { F.Println("PHP中文网(www.php.cn)") F.Println("Golang Pakckage import") }
After the program is run, the console output is as follows:
PHP中文网(www.php.cn) Golang Pakckage import
We use the alias reference method to introduce the system's built-in fmt package, and give the fmt package an alias of F. In the main function, we can no longer use the fmt. method to use the fmt package, and can only use the form of F. Came to use.
3. Use the omission method to import
Use the omission method to introduce the system’s built-in fmt package
package main //通过使用省略方式引入系统内置的 fmt 包 import ( . "fmt" ) func main() { Println("PHP中文网(www.php.cn)") Println("Golang Pakckage import") }
After the program is run, the console output is as follows:
PHP中文网(www.php.cn) Golang Pakckage import
We use omission to introduce the system's built-in fmt package. In the main function, we can no longer use the fmt. method to use the fmt package, but can directly use the functions of the fmt package.
4. Only execute the package init function to introduce
Introduce the system's built-in strconv package by only executing the package init function
package main //通过仅执行包 init 函数方式引入系统内置的 strconv 包 import ( "fmt" _ "strconv" ) func main() { fmt.Println("PHP中文网(www.php.cn)") fmt.Println("Golang Pakckage import") }
After the program is run, the console output is as follows:
PHP中文网(www.php.cn) Golang Pakckage import
We introduce the system's built-in strconv package by only executing the package init function. If we do not add _ in front of the package "strconv", the program will report an error.
Because golang does not allow the import of unused packages, so we add _ in front to indicate that we do not need to use the functions in the package, but only execute the init function of the package.
Go language package reference tutorial summary
There are four reference formats for package references in Golang, which are: using standard reference methods and using alias reference methods. Import, use omission to import and only execute the package init function.
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