Result Value Type about ojg HOT 4 CLOSED

So you are referring to the val := x.Get(obj) call I assume. Using a JSONPath to retrieve values can match more than one value to the result must be some kind of slice. Since the retrieved values can be of any type, the interface{} type must be used to cover all those cases. So a slice an "any" is []interface{}. To retrieve a single value you can use x.First(obj) which returns the first match as an interface{}. Returned value can aways be asserted to be the actual type so for example if the return from x.First(obj) is actually a string and that is expected then you could do something like str, ok := x.First(obj).(string). In that case, if ok is true then str will be the string value. You could also use the OjG alt.String() function if that suits your needs better.

To answer your questions directly:

1. The result of Get() is always a []interface{} as declared. It a feature of go that declaring the return type always results in that return type.
2. For a single value use First() instead. If a string is expected then assert as described above or use alt.String().
3. I wasn't sure what you were asking on this one. There really isn't anything to parse from the result. If you attempt to assert that a []interface{} is an []int64 that will fail at compile time. You can iterate over the result and assert that each element is an int64 though.

Thank you for your clearly answer!!! It completely solves my problem!

from ojg.

OjG has many functions. Can you tell me what function you are referring to?

from ojg.

Sorry, my fault.

here is my code:

obj ,_ := oj.ParseString(jsonString)
x, _ := jp.ParseString(jsonPath)
val := x.Get(obj)

from ojg.

So you are referring to the val := x.Get(obj) call I assume. Using a JSONPath to retrieve values can match more than one value to the result must be some kind of slice. Since the retrieved values can be of any type, the interface{} type must be used to cover all those cases. So a slice an "any" is []interface{}. To retrieve a single value you can use x.First(obj) which returns the first match as an interface{}. Returned value can aways be asserted to be the actual type so for example if the return from x.First(obj) is actually a string and that is expected then you could do something like str, ok := x.First(obj).(string). In that case, if ok is true then str will be the string value. You could also use the OjG alt.String() function if that suits your needs better.

To answer your questions directly:

1. The result of Get() is always a []interface{} as declared. It a feature of go that declaring the return type always results in that return type.
2. For a single value use First() instead. If a string is expected then assert as described above or use alt.String().
3. I wasn't sure what you were asking on this one. There really isn't anything to parse from the result. If you attempt to assert that a []interface{} is an []int64 that will fail at compile time. You can iterate over the result and assert that each element is an int64 though.

from ojg.