golang 的interface接口类型断言

x.(T)TxxTx.(type)switch

x.(type)

func checkType(args ...interface{}) {  
    for _, arg := range args {  
        switch arg.(type) {  
            case int:  
                fmt.Println(arg, "is an int value.")  
            case string:  
                fmt.Println(arg, "is a string value.")  
            case int64:  
                fmt.Println(arg, "is an int64 value.")  
            default:  
                fmt.Println(arg, "is an unknown type.")  
        }  
    }  
}  

x.(type)x.(T)xinterface{}

var num interface{} = 1  //  num.(int) 可以执行
var num int = 1 // num.(int) 编译失败 invalid type assertion: num.(int) (non-interface type int on left)

x.(T)

v, ok := x.(int)

oktruexintv