Compilation of community discussion and communication platform for golang anonymous functions and closures

Question: What are anonymous functions and closures in Go language? Answer: Anonymous function: A function that does not require an explicit declaration of a name. Closure: A function defined within another function can reference variables in the scope of its outer function and still exist when the closure is called.

#Anonymous functions and closures in Go language

Anonymous functions

Anonymous functions are functions that do not require an explicit declaration of a name. Use the func keyword, followed by the function body, like this:

func() {
    fmt.Println("这是一个匿名函数")
}

Closure

A closure is a function defined inside another function that can reference outside of it Variables in the function scope that persist when the closure is called. This allows the closure to access data from the outer scope after execution.

func outer() func() {
    x := 10
    return func() {
        fmt.Println("x 为", x)
    }
}

Practical case

Anonymous functions as callbacks

Anonymous functions are usually used as callbacks and are executed when the asynchronous operation is completed. For example:

func main() {
    // 使用匿名函数作为回调
    httpClient.Get("https://golang.org", func(resp *http.Response, err error) {
        if err != nil {
            fmt.Println("请求失败")
            return
        }
        defer resp.Body.Close()
        io.Copy(os.Stdout, resp.Body)
    })
}

Closures are used to encapsulate data

Closures can be used to encapsulate data and functions, allowing access and modification of this data without the need for other external functions. For example:

func main() {
    // 使用闭包封装共享状态
    counter := func() int {
        var i int
        return func() int {
            i++
            return i
        }
    }()

    fmt.Println(counter())    // 1
    fmt.Println(counter())    // 2
    fmt.Println(counter())    // 3
}

Conclusion:

Anonymous functions and closures provide powerful tools in the Go language for writing flexible, maintainable code. By understanding their purpose and how they work, you can take full advantage of their capabilities.

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