go语言 array_sum 求和方法（反射+泛型）

给定一个任意类型的切片/数组，求所有元素的值

原型：ArraySum(input interface{}) (sum float64, err error)

功能：对 input 切片中的所有数据求和，结果累计在 sum 中输出

代码实现：

package reflect

import (
    "reflect"
    "errors"
    "strconv"
)

// 数组切片求和
func ArraySum(input interface{}) (sum float64, err error) {
    list := reflect.ValueOf(input)
    switch reflect.TypeOf(input).Kind() {
    case reflect.Slice, reflect.Array:
        for i := 0; i < list.Len(); i++ {
            val := list.Index(i)
            v, err := toFloat64(val.Interface())
            if err != nil {
                return 0, err
            }
            sum += v
        }
    default:
        return 0, errors.New("input must be slice or array")
    }
    return
}


func toFloat64(in interface{}) (f64 float64, err error) {
    switch val := in.(type) {
    case float64:
        return val, nil
    case float32:
        return float64(val), nil
    case uint8:
        return float64(val), nil
    case uint16:
        return float64(val), nil
    case uint32:
        return float64(val), nil
    case uint64:
        return float64(val), nil
    case uint:
        if strconv.IntSize == 32 || strconv.IntSize == 64 {
            return float64(val), nil
        }
        return 0, errors.New("convert uint to float64 failed")
    case int8:
        return float64(val), nil
    case int16:
        return float64(val), nil
    case int32:
        return float64(val), nil
    case int64:
        return float64(val), nil
    case int:
        if strconv.IntSize == 32 || strconv.IntSize == 64 {
            return float64(val), nil
        }
        return 0, errors.New("convert int to float64 failed")
    case bool:
        if val {
            f64 = 1
        }
        return
    case string:
        f64, err = strconv.ParseFloat(val, 64)
        if err == nil {
            return
        }
        return 0, errors.New("convert string to float64 failed")
    default:
        return 0, errors.New("convert to float64 failed")
    }
}

测试：

func TestArraySum(t *testing.T) {
	numberInt := []int{1,2,3,4}
	val, err := ArraySum(numberInt)
	fmt.Println(val, err)

	numberStr := []string{"1","2","3","4"}
	val, err = ArraySum(numberStr)
	fmt.Println(val, err)
}

测试结果：

10 <nil>
10 <nil>