douxian1923 2018-07-03 18:43
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如何在Go中通过反射获取地图界面的值?

I'm struggling to get the value of an interface map in Go.

val := reflect.ValueOf(Schema)
fmt.Println("VALUE = ", val)
fmt.Println("KIND = ", val.Kind())
if val.Kind() == reflect.Map {
    fmt.Println("len = ", val.Len())
    for key, element := range val.MapKeys() {
        fmt.Println(key, element) // how to get the value?
    }
}

This outputs:

VALUE =  map[testString:foobar testInt:1 testBoolean:true testNumber:1 testDateTime:2017-10-06 08:15:30 +0100 +0100]
KIND =  map
len =  5
0 testString
1 testInt
2 testBoolean
3 testNumber
4 testDateTime

My question:
How can I get the type and value of the map items?

  • 写回答

1条回答 默认 最新

  • duanboxue3422 2018-07-03 19:19
    关注

    You were close, you can use the key returned form MapKeys and then use MapIndex to get the value of the map key. Below I use a switch statement to convert the value of the interface to the correct type.

    package main
    
    import (
        "fmt"
        "reflect"
    )
    
    func main() {
        Schema := map[string]interface{}{}
        Schema["int"] = 10
        Schema["string"] = "this is a string"
        Schema["bool"] = false
    
        val := reflect.ValueOf(Schema)
        fmt.Println("VALUE = ", val)
        fmt.Println("KIND = ", val.Kind())
    
        if val.Kind() == reflect.Map {
            for _, e := range val.MapKeys() {
                v := val.MapIndex(e)
                switch t := v.Interface().(type) {
                case int:
                    fmt.Println(e, t)
                case string:
                    fmt.Println(e, t)
                case bool:
                    fmt.Println(e, t)
                default:
                    fmt.Println("not found")
    
                }
            }
        }
    }
    

    Program Output:

    VALUE =  map[int:10 string:this is a string bool:false]
    KIND =  map
    int 10
    string this is a string
    bool false
    
    本回答被题主选为最佳回答 , 对您是否有帮助呢?
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