go-reflect

I am using reflect package to get the type of arbitrary array, but getting prog.go:17: cannot use sample_array1 (type []int) as type []interface {} in function argument [process exited with non-zero status] How do I get the type from array? I know how to get it from value. func GetTypeArray(arr []interface{}) reflect.Type { return reflect.TypeOf(arr[0]) } http://play.golang.org/p/sNw8aL0a5f Change: GetTypeArray(arr []interface{}) to: GetTypeArray(arr interface{}) By the way, []int is not an array but a slice of integers. The fact that you're indexing the slice is unsafe - if it's empty, you'll

In Go, how do you check if an object responds to a method? For example, in Objective-C this can be achieved by doing: if ([obj respondsToSelector:@selector(methodName:)]) { // if method exists [obj methodName:42]; // call the method } A simple option is to declare an interface with just the method you want to check for and then do a type assert against your type like; i, ok := myInstance.(InterfaceImplementingThatOneMethodIcareAbout) // inline iface delcataration example i, ok = myInstance.(interface{F()}) You likely want to use the reflect package if you plan to do anything too crazy with

Basically if I have a slice or array of any arbitrary functions, how can I select only the ones that return int, or select only the ones that take ints? I figured that I would need to use the reflect package, but just reading the docs didn't really help me figure out exactly how to do it. This program prints the functions taking an int as parameter or returning an int : package main import ( "fmt" "reflect" ) func main() { funcs := make([]interface{}, 3, 3) // I use interface{} to allow any kind of func funcs[0] = func (a int) (int) { return a+1} // good funcs[1] = func (a string) (int) {

Because not all types are comparable, e.g. a slice. So we can't do this var v ArbitraryType v == reflect.Zero(reflect.TypeOf(v)).Interface() Edit - Solution reflect.DeepEqual var v ArbitratyType zero := reflect.Zero(reflect.TypeOf(v)).Interface() isZero := reflect.DeepEqual(v, zero) Go documentation about reflect.DeepEqual DeepEqual tests for deep equality. It uses normal == equality where possible but will scan elements of arrays, slices, maps, and fields of structs. Peter Noyes See this post: Golang: Reflection - How to get zero value of a field type Basically you need to have special cases

Been having one last issue with my code which involves the .Call function in the reflect package. So I'm making a call such as this: params := "some map[string][]string" in := make([]reflect.Value,0) return_values := reflect.ValueOf(&controller_ref).MethodByName(action_name).Call(in) where the method I'm making the .Call to is as follows: func (c *Controller) Root(params map[string][]string) map[string] string{} What I don't quite understand is how to manipulate the "in" variable in order to properly pass the map I need to into the function. I see that the second parameter in the make() is the