Analysis of the role and usage of fn in Go language

The role and usage analysis of fn in Go language

In Go language, fn is a keyword used to define functions. A function is an independent block of code that can be called multiple times to perform a specific task. In Go language, functions are first-class citizens and can be passed as parameters to other functions and can also be used as return values. This article will analyze in detail the role and specific usage of fn in the Go language, and provide code examples to illustrate.

1. Define function

In Go language, use the fn keyword to define a function. The syntax is as follows:

fn 函数名(参数列表) 返回值类型 {
    // 函数体
}

Where, the function name is The identifier of the function, the parameter list specifies the input parameters of the function, and the return value type is used to specify the return type of the function. The following is a simple function example for calculating the sum of two integers:

fn add(a int, b int) int {
    return a + b
}

2. Call of function

After defining the function, you can call the function through the function name , pass in the corresponding parameters and get the return value. Functions can be called directly or passed as arguments to other functions. The following is an example of calling the add function:

result := add(3, 5)
fmt.Println(result) // 输出: 8

3. Anonymous function

In addition to using the fn keyword to define named functions, the Go language also supports the definition of anonymous functions, namely Without specifying a function name, define the function body directly. Anonymous functions can be assigned directly to variables or passed as parameters to other functions. The following is an example of using anonymous functions:

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

4. Function as parameter

In Go language, functions can be passed as parameters to other functions. This feature makes functions More flexible. Here is an example that accepts a function as a parameter:

func apply(f func(int, int) int, a, b int) int {
    return f(a, b)
}

result := apply(add, 3, 5)
fmt.Println(result) // 输出: 8

5. Function as a return value

In addition to being passed as a parameter to other functions, a function can also be passed as a parameter to another function. return value. The following is an example of returning a function:

func getAddFunction() func(int, int) int {
    return add
}

addFn := getAddFunction()
result := addFn(3, 5)
fmt.Println(result) // 输出: 8

Summary: The fn keyword is used to define functions in the Go language. Functions are independent blocks of code used to perform specific tasks. Functions can be called directly, passed as arguments to other functions, and as return values. The flexibility of functions makes Go language more convenient and efficient in programming. I hope that through the analysis and code examples of this article, readers can better understand the role and usage of fn in the Go language.

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