CODEWITHSUNDEEP
goreflectiongo-reflect
Rick Smith
Rick Smith

Reputation: 9251

How to I convert reflect.New's return value back to the original type

I'm using reflection in go and I noticed the oddity expressed below:

package main

import (
        "log"
        "reflect"
)

type Foo struct {
        a int
        b int
}

func main() {
        t := reflect.TypeOf(Foo{})
        log.Println(t) // main.Foo
        log.Println(reflect.TypeOf(reflect.New(t))) // reflect.Value not main.Foo
}

How can I convert the reflect.Value back to main.Foo?

I've provided a go playground for convenience.

Upvotes: 4

Views: 1985

Answers (1)

Mr_Pink
Mr_Pink

Reputation: 109443

You use the Value.Interface method to get an interface{}, then you can use a type assertion to extract value:

t := reflect.TypeOf(Foo{})
val := reflect.New(t)
newT := val.Interface().(*Foo)

If you don't want a pointer, you use the reflect.Zero function to create a zero-value for the type. You then use the same interface and type assertion method to extract the new value.

t := reflect.TypeOf(Foo{})
f := reflect.Zero(t)
newF := f.Interface().(Foo)

Upvotes: 9

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