英文:
Why int32(0) is not reflect.DeepEqual to type Zero in Golang?
问题
我在go-swagger包中找到了这种验证方式。
// Required validates an interface for requiredness
func Required(path, in string, data interface{}) *errors.Validation {
val := reflect.ValueOf(data)
if reflect.DeepEqual(reflect.Zero(val.Type()), val) {
return errors.Required(path, in)
}
return nil
}
我尝试使用它，但它对我产生了一些疑问。
为什么下面的语句不是一个正确的陈述？
exper := int32(0)
reflect.DeepEqual(
reflect.Zero(reflect.ValueOf(exper).Type()),
reflect.ValueOf(exper)
)
英文:
I found this sort of validation in go-swagger package.
// Required validates an interface for requiredness
func Required(path, in string, data interface{}) *errors.Validation {
val := reflect.ValueOf(data)
if reflect.DeepEqual(reflect.Zero(val.Type()), val) {
return errors.Required(path, in)
}
return nil
}
I tried to use it and it forced me for some thoughts.
Why the following is not a true statement?
exper := int32(0)
reflect.DeepEqual(
reflect.Zero(reflect.ValueOf(exper).Type()),
reflect.ValueOf(exper)
)
答案1
得分: 5
请查看reflect.Value的Godoc文档：
> 在两个Value上使用==运算符不会比较它们所表示的底层值，而是比较Value结构体的内容。要比较两个Value，请比较Interface方法的结果。
package main
import "reflect"
func main() {
//var i int32
exper := int32(0)
r := reflect.DeepEqual(
reflect.Zero(reflect.ValueOf(exper).Type()).Interface(),
reflect.ValueOf(exper).Interface(),
)
println(r) // true
}
英文:
Please check the godocs of reflect.Value:
> Using == on two Values does not compare the underlying values they
> represent, but rather the contents of the Value structs. To compare
> two Values, compare the results of the Interface method.
package main
import "reflect"
func main() {
//var i int32
exper := int32(0)
r := reflect.DeepEqual(
reflect.Zero(reflect.ValueOf(exper).Type()).Interface(),
reflect.ValueOf(exper).Interface(),
)
println(r) // true
}
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