Let's talk about some advanced usage of Golang

The emergence of Go language makes our development more efficient, safer and simpler. With a simple code style and efficient performance, it has become the first choice of many developers and companies. However, as we deepen our understanding and use of the Go language, sometimes we need more advanced and flexible writing methods to cope with different work needs. So, here are some advanced usages of Golang.

1. Golang defer statement

#defer statement is a major feature of the Go language. It allows the function to execute the following statements after it is executed. For example:

func f() (n int) {
    defer func() {
        n++
    }()
    return 1
}

func main() {
    i := f()
    println(i)
}

The running result is 2, and 2 is returned after executing n . What should be noted here is that defer will only be executed after the function is executed, even if panic appears in the function.

2. Golang type assertion

Type assertion can convert an interface type to another interface type or a concrete type. For example:

var obj interface{}
var str string = "hello"

obj = str

if s, ok := obj.(string); ok {
    fmt.Println(s)
}

Here str is assigned to an interface type variable obj, and then use type assertion to convert obj to string type and judge, if successful, print hello. It should be noted that if the conversion fails during type assertion, false will be returned instead of panic.

3. Golang Range statement

range statement can be used to loop and iterate arrays, slices, maps, strings, channels and other types. For example:

for i, v := range []int{1, 2, 3} {
    fmt.Println(i, v)
}

Here, a range loop is used to iterate a slice of type int. The first value is the index, and the second value is the value in the slice.

4. Golang custom methods

Custom methods in Go language are similar to those in Java, and methods can be defined for any type. For example:

type MyInt int

func (m MyInt) Plus(n int) int {
    return int(m) + n
}

func main() {
    var m MyInt = 1
    fmt.Println(m.Plus(2))
}

A custom type MyInt is defined here, and then a Plus method is defined for it. The addition operation is implemented by converting the MyInt type to the int type.

5. Golang closure function

A closure function refers to a function that can access free variables. For example:

func Adder() func(int) int {
    sum := 0
    return func(x int) int {
        sum += x
        return sum
    }
}

func main() {
    a := Adder()
    fmt.Println(a(1))
    fmt.Println(a(2))
}

Here defines a function Adder with a return type of func(int) int, which returns an internal function. This internal function has access to the free variable sum in the Adder function and adds x to sum.

Through the above advanced usage, we can better cope with different Go language development needs and make our code more concise and flexible. I hope this article will be helpful to the majority of Go language developers.

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