What are the commonly used functions in Go language?

What are the commonly used functions in Go language? ——Explore commonly used functions and their usage in Go language

As a popular statically typed programming language, Go language is widely used in various fields, such as server-side development, network programming, cloud computing, etc. . In the Go language, functions, as the basic code organization unit, are an important part of program running. This article will explore the commonly used functions and their usage in the Go language to help readers better grasp the core features of this language.

1. Function declaration and call
The function is declared starting with the keyword "func" in the Go language. The syntax is as follows:

func 函数名(参数列表) 返回值类型 {
    // 函数体
}

Among them, the parameter list and return value type can Omitted, if the function has no return value, the return value type does not need to be written.

1. Example: Define a simple function

   func greet() {
    fmt.Println("Hello, World!")
   }

The function is called through the function name. Just call the function name directly in the code:

greet()

2. Commonly used built-in functions
The Go language has many commonly used built-in functions, such as "len", "append", "copy", etc. Below we introduce their usage respectively.

1. lenFunction: used to get the length of slices, arrays, strings, etc.

   package main
   
   import "fmt"
   
   func main() {
    slice := []int{1, 2, 3, 4, 5}
    fmt.Println(len(slice)) // 输出：5
   }

2. append Function: used to append elements to the slice

   package main
   
   import "fmt"
   
   func main() {
    slice := []int{1, 2, 3}
    slice = append(slice, 4, 5)
    fmt.Println(slice) // 输出：[1 2 3 4 5]
   }

3. copy Function: used to copy the slice

   package main
   
   import "fmt"
   
   func main() {
    slice1 := []int{1, 2, 3}
    slice2 := make([]int, 3)
    copy(slice2, slice1)
    fmt.Println(slice2) // 输出：[1 2 3]
   }

3. Anonymous functions and closures
In the Go language, functions can be passed as variables, including anonymous functions and closures. Anonymous functions have no function names and can be defined and called directly in the code. Closures refer to functions defined inside the function and can access variables of external functions.

1. Example: anonymous function

   package main
   
   import "fmt"
   
   func main() {
    add := func(a, b int) int {
        return a + b
    }
   
    result := add(3, 4)
    fmt.Println(result) // 输出：7
   }

2. Example: closure

   package main
   
   import "fmt"
   
   func outer() func() {
    count := 0
    return func() {
        count++
        fmt.Println("Count:", count)
    }
   }
   
   func main() {
    counter := outer()
    counter() // 输出：Count: 1
    counter() // 输出：Count: 2
   }

4. defer and panic/recover
In Go language, defer is used to delay the execution of functions, panic is used to trigger runtime panic, and recover is used to capture panic and process it. These three features work together to ensure program stability.

1. Example: use of defer

   package main
   
   import "fmt"
   
   func main() {
    defer fmt.Println("World!")
    fmt.Print("Hello, ")
   }

   The output result is: "Hello, World!"

2. Example: panic and The use of recover

   package main
   
   import "fmt"
   
   func recoverFromPanic() {
    if r := recover(); r != nil {
        fmt.Println("Recovered from panic:", r)
    }
   }
   
   func potentiallyPanic() {
    defer recoverFromPanic()
    panic("Panic!")
   }
   
   func main() {
    potentiallyPanic()
    fmt.Println("Program continues")
   }

   The output results are: "Recovered from panic: Panic!" and "Program continues"

   Through the introduction of this article, readers can have a deeper understanding Commonly used functions and their usage in Go language, including function declaration and calling, commonly used built-in functions, anonymous functions and closures, defer and panic/recover. Mastering this knowledge will help readers better apply Go language for development and improve programming efficiency. I hope this article can be helpful to readers, thank you for reading!

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