If I want to cast interface{} to float64
interface{} could be int8 int16 int32 int64 float32.....
What is the proper way.
consider a generic function for min
func Min(a T, b T) T {
}
What is the best way to implement it in go
2017-01-12 10:52 GMT+08:00 Dan Kortschak <dan.kortsc...@adelaide.edu.au>:
> What are you trying to do?
>
> The behaviour of LimRange as you have it here is to return the float64
> value of x if it is a float64, zero if it is another numerical type in
> the case list and NaN if it is none of those.
>
> I would suggest you read https://golang.org/ref/spec#Switch_statements
> particularly Type Switches where it says
>
> ```
> In clauses with a case listing exactly one type, the variable has that
> type; *otherwise, the variable has the type of the expression in the
> TypeSwitchGuard*.
> ```
>
> This means that in the case as you have it below with
> `case int,int8,int16,int32,float32,float64:` the type of v must be the
> type of x, which is interface{}. You cannot convert interface{} to
> float64.
>
> On Wed, 2017-01-11 at 18:35 -0800, hui zhang wrote:
> > This is a compile error, so I don't think this matter
> > I modify the code , add float , it is the same.
> >
> > func LimRange(x, low, high interface{}) float64 {
> > var fx, flow, fhigh float64
> > switch v := x.(type) {
> > case int: //OK
> > case int8:
> > case int16:
> > case int32:
> > case float32:
> > case float64:
> > return float64(v) //OK
> >
> > default:
> > return math.NaN()
> > }
> >
> > switch v := x.(type) {
> > case int,int8,int16,int32,float32,float64:
> > return float64(v) //Error: cannot convert v (type
> > interface {}) to type float64: need type assertion
> > default:
> > return math.NaN()
> > }
> >
> > a :=1
> > switch a {
> > case 1,2: //OK
> > println("1,2")
> > }
> >
> > return math.Max(math.Min(fx, fhigh), flow)
> > }
> >
> >
>
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