Let’s talk about knowledge related to Golang forced transfer

When using Golang for development, we often encounter situations where type conversion is required, which is called forced type conversion or forced conversion. Coercion can convert a variable from one type to another, which is very useful when processing data. This article will introduce the relevant knowledge of Golang forced transfer, including data type conversion, pointer conversion, interface conversion, etc.

Forced conversion of data types

In Golang, the forced conversion of data types requires the use of parentheses to include the variable, and then add the type name of the data type that needs to be converted in front. For example, to cast a string to an integer, the example is as follows:

str := "123"
num, err := strconv.Atoi(str)
if err == nil {
    fmt.Println(num)
}

In this example, the strconv.Atoi function converts the string to an integer and returns a ## A value of type #int. In addition to the strconv.Atoi function, there are some other functions that can perform type conversion, such as strconv.ParseBool, strconv.ParseFloat, strconv .ParseInt etc.

In addition to using functions for type conversion, you can also use coercion operators for type conversion. For example, to convert a

float64 type to the int type, the example is as follows:

f := 1.2
i := int(f) // f 被强制转换为 int 类型
fmt.Println(i)

Force conversion of pointer

In Golang, pointer variables are stored The memory address of a variable can be accessed or modified through a pointer. Pointer variables can also be forcibly transferred.

To cast a pointer, you need to use parentheses to include the pointer variable, and then add the type name of the pointer type that needs to be converted in front. For example, to convert a pointer variable of type

*int to a pointer variable of type *string, the sample code is as follows:

num := 123
ptr := &num //ptr 是一个 *int 类型的指针变量
str := (*string)(unsafe.Pointer(ptr)) // str 是一个 *string 类型的指针变量

In this example, we can see

unsafe.Pointer is used to perform pointer type casting. Although using unsafe.Pointer is very convenient, it is not recommended due to its unsafety. If you need to use unsafe.Pointer for pointer casting, please pay attention to comply with Golang's specifications and rules.

Forced transfer of interfaces

In Golang, interfaces are a key mechanism used to support object-oriented programming. Interface variables can store any type variable that implements the interface, and when calling the method of the interface variable, the method corresponding to the type will be dynamically parsed and called.

Interface variables can be coerced into type variables that implement the interface. This process is called type assertion. The syntax of type assertion is

interface{}.(type). For example, to force conversion of an interface variable i to a string type, the sample code is as follows:

var i interface{}
i = "hello, world"
str := i.(string) // i 被强制转换为 string 类型
fmt.Println(str)

It should be noted that when performing forced type conversion of the interface, if the conversion fails, the program

panic exception will be thrown directly. You can avoid this by using the form _, ok := i.(Type).

Summary

Golang forced transfer is a very useful feature when processing data. Whether it is the coercion of data types, pointer types or interface types, Golang's specifications and principles need to be followed. Therefore, when you use Golang for development, be sure to follow Golang's development specifications and use the force transfer feature with caution.

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