2015-01-15 19:55 阅读 116


In go, is it possible to cast variables dynamically somehow?

For example, if a simple cast would be:

var intAge  = interfaceAge.(int)

What if I do not know that age is an int in advance? A simple way of writing it would be

var x = getType()
var someTypeAge = interfaceAge(.x)

Is there a way of achieving something like this? The reflect package gives some ways of determining or casting a type at runtime - but I couldn't find anything like the above mentioned (a generic scheme that would work for all types).

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    dongmufen8105 dongmufen8105 2015-01-15 20:17

    No you can't. Go is a static typed language. The type of a variable is determined at compile time.

    If you want to determine dynamically the typeof an interface{} you could use type switching:

    var t interface{}
    t = functionOfSomeType()
    switch t := t.(type) {
        fmt.Printf("unexpected type %T", t)       // %T prints whatever type t has
    case bool:
        fmt.Printf("boolean %t
    ", t)             // t has type bool
    case int:
        fmt.Printf("integer %d
    ", t)             // t has type int
    case *bool:
        fmt.Printf("pointer to boolean %t
    ", *t) // t has type *bool
    case *int:
        fmt.Printf("pointer to integer %d
    ", *t) // t has type *int
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