golang interface 转 int string slice struct 类型

interface{}intstringstructsliceinterface{}

package main
import (
    "fmt"
)
type User struct{
    Name string
}
func main() {
    any := User{
        Name: "fidding",
    }
    test(any)
    any2 := "fidding"
    test(any2)
    any3 := int32(123)
    test(any3)
    any4 := int64(123)
    test(any4)
    any5 := []int{1, 2, 3, 4, 5}
    test(any5)
}
 
// value 允许为任意值
func test(value interface{}) {
    ...
}　

User结构体Nametype assertionstype switches

package main
import (
    "fmt"
)
type User struct{
    Name string
}
func main() {
    any := User{
        Name: "fidding",
    }
    test(any)
    any2 := "fidding"
    test(any2)
    any3 := int32(123)
    test(any3)
    any4 := int64(123)
    test(any4)
    any5 := []int{1, 2, 3, 4, 5}
    test(any5)
}
func test(value interface{}) {
    switch value.(type) {
    case string:
        // 将interface转为string字符串类型
        op, ok := value.(string)
        fmt.Println(op, ok)
    case int32:
        // 将interface转为int32类型
        op, ok := value.(int32)
        fmt.Println(op, ok)
    case int64:
        // 将interface转为int64类型
        op, ok := value.(int64)
        fmt.Println(op, ok)
    case User:
        // 将interface转为User struct类型，并使用其Name对象
        op, ok := value.(User)
        fmt.Println(op.Name, ok)
    case []int:
        // 将interface转为切片类型
        op := make([]int, 0)  //[]
        op = value.([]int)
        fmt.Println(op)
    default:
        fmt.Println("unknown")
    }
}

输出：

fidding true
 
fidding true
 
123 true
 
123 true
 
[]
 
[1 2 3 4 5]

.()

// 如果转换失败ok=false，转换成功ok=true
res, ok := anyInterface.(someType)

anyInterface.(type)switch case