# Go Tricks - unpack slice to struct fields

Use `reflect`, in this example, we only show to unpack an int slice to a struct whose fields are all int type.

```go
package main

import (
	"errors"
	"fmt"
	"reflect"
)

type Location struct {
	X int
	Y int
	Z int
}

func (loc Location) String() string {
	return fmt.Sprintf("X: %d, Y: %d, Z: %d", loc.X, loc.Y, loc.Z)
}

func unpackIntSliceToStruct(slice []int, st interface{}) error {
	s := reflect.ValueOf(st).Elem()
	if s.Kind() != reflect.Struct {
		return errors.New("st must be a struct pointer")
	}
	l := s.NumField()
	if len(slice) != l {
		return errors.New("number of fields doesn't match")
	}
	for i := 0; i < l; i++ {
		f := s.FieldByIndex([]int{i})
		if f.CanAddr() {
			f.SetInt(int64(slice[i]))
		}
	}
	return nil
}

func main() {
	points := []int{1, 2, 3}
	loc := Location{}
	err := unpackIntSliceToStruct(points, &loc)
	if err != nil {
		fmt.Println(err)
		return
	}
	fmt.Println(loc)
}
```

Result:

```
X: 1, Y: 2, Z: 3
```