about golang interface loop

I wanto print a complicate dataset like bellowing

package main
import (
	"fmt"
	// "reflect"
)

func main() {

	var initData []interface{}
	initData[0] = map[string]interface{}{
		"name": "k1",
		"type": "line",
		"data": []int{1, 2, 3, 4},
	}

	initData[1] = map[string]interface{}{
		"name": "k2",
		"type": "circle",
		"data": []int{11, 12, 13, 14},
	}
   
	for _, data := range initData {
		for k, v := range data {
			fmt.Println(k)
			for _, sv := range v {
				fmt.Println("  " + sv)
			}
		}

	}

}

but get an error

./maps-in-maps.go:56: cannot range over data (type interface {})

any help? to try to concert the interface typed dataset to interable like arry or slice

You must type assert each interface{} level first, in this case, use a type assertion at map[string]interface{} level since we know a definite type, and a type switch to check anticipated types for each nested value in the next level.

initData := []interface{}{
		map[string]interface{}{
			"name": "k1",
			"type": "line",
			"data": []int{1, 2, 3, 4},
		},

		map[string]interface{}{
			"name": "k2",
			"type": "circle",
			"data": []int{11, 12, 13, 14},
		},
	}

	for _, data := range initData {
		for _, v := range data.(map[string]interface{}) {
			switch t := v.(type) {
			case string, []int:
				fmt.Println(t)
			default:
				fmt.Println("wrong type")			
			}
		}
	}
}

Run playground here.