golang获取变量或对象类型的几种方式总结
Byte-Coder 人气:0fmt.Printf("%T")方式
示例：
var1 := "hello world"
fmt.Printf("var1 = %T\n", var1)这个是最简单，也是最推荐的在at rumtime时获取变量类型的方式，
用fmt.Printf("%T")实现返回变量类型的函数
由此衍生出可复用获取变量或者对象type的函数，如下面函数，直接返回变量类型
func typeofVariable(variable interface{}) string {
return fmt.Sprintf("%T", variable)
}reflect.TypeOf方式
示例：
var1 := "hello world"
fmt.Printf("var1: %s\n", reflect.TypeOf(var1))用 reflect包里的函数 TypeOf()来实现，用起来相对来说复杂些，如果只是单纯地想在runtime时获取一下变量类型，还是推荐第一种方式
用reflect.TypeOf实现返回变量类型的函数
由此衍生出可复用获取变量或对象type的函数，如下面函数，直接返回变量类型
func typeofVariable(variable interface{}) string {
return reflect.TypeOf(variable).String()
}reflect.ValueOf.Kind()方式
示例：
var1 := "hello world" fmt.Println(reflect.ValueOf(var1).Kind())
用 reflect.ValueOf.Kind()实现返回变量类型的函数
func typeofVariable(variable interface{}) string {
return reflect.ValueOf(variable).Kind().String()
}断言方式
func typeofObject(variable interface{}) string {
switch variable.(type) {
case string:
return "string"
case int:
return "int"
case float32:
return "float32"
case float64:
return "float64"
case bool:
return "boolean"
case []string:
return "[]string"
case complex128:
return "complex128"
case complex64:
return "complex64"
case map[string]float64:
return "map"
case Employee:
return "Employee"
default:
return "unknown"
}
}代码示例：
package main
import (
"fmt"
"reflect"
)
type Employee struct {
name string
age int
salary float64
}
// 4 ways to return a variable's type at runtime
func typeofObject(variable interface{}) string {
switch variable.(type) {
case string:
return "string"
case int:
return "int"
case float32:
return "float32"
case float64:
return "float64"
case bool:
return "boolean"
case []string:
return "[]string"
case complex128:
return "complex128"
case complex64:
return "complex64"
case map[string]float64:
return "map"
case Employee:
return "Employee"
default:
return "unknown"
}
}
func main() {
var1 := "hello world"
var2 := 10
var3 := 2.55
var4 := []string{"BeiJing", "ShangHai", "ShenZhen"}
var5 := map[string]float64{"BeiJing": 3.2, "ShaiHai": 1.2}
var6 := complex(3,4)
var7 := true
var8 := Employee{"Sam",30,15000.5}
fmt.Println("############### Using %T with Printf ########################")
fmt.Printf("var1 = %T\n", var1)
fmt.Printf("var2 = %T\n", var2)
fmt.Printf("var3 = %T\n", var3)
fmt.Printf("var4 = %T\n", var4)
fmt.Printf("var5 = %T\n", var5)
fmt.Printf("var6 = %T\n", var6)
fmt.Printf("var7 = %T\n", var7)
fmt.Printf("var8 = %T\n", var8)
fmt.Println("###############Using reflect.TypeOf Function #######################")
fmt.Printf("var1: %s\n", reflect.TypeOf(var1))
fmt.Printf("var2: %s\n", reflect.TypeOf(var2))
fmt.Printf("var3: %s\n", reflect.TypeOf(var3))
fmt.Printf("var4: %s\n", reflect.TypeOf(var4))
fmt.Printf("var5: %s\n", reflect.TypeOf(var5))
fmt.Printf("var6: %s\n", reflect.TypeOf(var6))
fmt.Printf("var7: %s\n", reflect.TypeOf(var7))
fmt.Printf("var8: %s\n", reflect.TypeOf(var8))
fmt.Println("###############Using reflect.ValueOf.Kind() ########################")
fmt.Println(reflect.ValueOf(var1).Kind())
fmt.Println(reflect.ValueOf(var2).Kind())
fmt.Println(reflect.ValueOf(var3).Kind())
fmt.Println(reflect.ValueOf(var4).Kind())
fmt.Println(reflect.ValueOf(var5).Kind())
fmt.Println(reflect.ValueOf(var6).Kind())
fmt.Println(reflect.ValueOf(var7).Kind())
fmt.Println(reflect.ValueOf(var8).Kind())
fmt.Println("################## Using Type assertions ###########################")
fmt.Println(typeofObject(var1))
fmt.Println(typeofObject(var2))
fmt.Println(typeofObject(var3))
fmt.Println(typeofObject(var4))
fmt.Println(typeofObject(var5))
fmt.Println(typeofObject(var6))
fmt.Println(typeofObject(var7))
fmt.Println(typeofObject(var8))
}
/*
几个复用的函数来判断变量的类型at runtime
// Using %T
func typeofVariable(variable interface{}) string {
return fmt.Sprintf("%T", variable)
}
// Using reflect.TypeOf()
func typeofVariable(variable interface{}) string {
return reflect.TypeOf(variable).String()
}
// Using reflect.ValueOf().Kind()
func typeofVariable(variable interface{}) string {
return reflect.ValueOf(variable).Kind().String()
}
*/结果演示：
总结
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