如何将接口数组转换为float

Question

bound :=  []interface{}{1.00, 1.00, 1.00, 1.00}
new_bound := bound.([]float32)
log.Println(new_bound)

How convert array of interface to array of float?

invalid type assertion: bound.([]float32) (non-interface type []interface {} on left)

And in real project

panic: interface conversion: interface is []interface {}, not []float32

Answer 1

In your example you have a slice where each item it contains is an interface{} rather than say, a single interface{} representing a []float32, for this reason you can't convert the whole collection so simply like that. Instead you have to iterate it and do a type assertion on each item in the collection. Here's an example; https://play.golang.org/p/dD4161xgaV

bound :=  []interface{}{1.00, 1.00, 1.00, 1.00}
new_bound := []float64{}
for _, v := range bound {
     new_bound = append(new_bound, v.(float64))
}

One other thing to note, those literals have their type implied and it's float64 so you actually need that here.

EDIT: Including this more optimized solution posted by OneOfOne;

func main() {
    bound := []interface{}{1.00, 1.10, 1.11, 1.111}
    new_bound := make([]float64, len(bound))
    for i := range bound {
        new_bound[i] = bound[i].(float64)
    }
    fmt.Println(new_bound)

}