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What is the role of the interface interface in Golang? many novices are not very clear about this. In order to help you solve this problem, the following editor will explain it in detail. People with this need can come and learn. I hope you can get something.

What is the interface interface

Interface is one of the basic features of the GO language. Can be understood as a type of specification or convention. Unlike java,C#, it does not need to show that it implements an interface, it does not inherit or subclass or "implements" keyword, but implicitly implements the methods in interface through the agreed form. As a result, interface in Golang makes coding more flexible and scalable.

How to understand interface in go language? Just remember the following three points:

1. Interface is a collection of method declarations

two。 An object of any type implements all the methods declared in the interface interface, indicating that the type implements the interface.

3. Interface can be used as a data type, and any object that implements this interface can assign values to the corresponding interface type variables.

Note:

1. Interface can be implemented by any object, and a type / object can also implement multiple interface.

two。 Method cannot be overloaded, for example, eat () eat (s string) cannot exist at the same time

Interface implementation

Package mainimport "fmt" type Phone interface {call ()} type NokiaPhone struct {} func (nokiaPhone NokiaPhone) call () {fmt.Println ("I am Nokia, I can call you!")} type ApplePhone struct {} func (iPhone ApplePhone) call () {fmt.Println ("I am ApplePhone, I can call you!")} func main () {var phone Phone phone = new (NokiaPhone) phone.call () phone = new (ApplePhone) phone.call ()}

Interface query

If interface An implements all the methods in interface B, then A can be converted to interface B.

If varName2, ok: = varName1. (interface2 | typeName); ok {/ / now the type of varName2 is changed from interface1 to interface2, or varName1 is not a variable of type typeName} else {/ / cannot convert interface, or varName1 is not a variable of type typeName

Interface {} Typ

The interface {} type does not declare any methods, commonly known as empty interfaces. Interface {} is very useful when we need to store any type of value, a bit similar to the C language void* type.

Package mainimport ("fmt") func PrintAll (vals [] interface {}) {for _, val: = range vals {fmt.Println (val)}} func main () {names: = [] string {"stanley", "david", "oscar"} vals: = make ([] interface {}, len (names) for I, v: = range names {vals [I] = v} PrintAll (vals)}

However, it should be noted that [] T cannot be assigned directly to [] interface {}

T: = [] int {1,2,3,4} var s [] interface {} = t

The following error is output at compile time:

Cannot use t (type [] int) as type [] interface {} in assignment

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