1/ Learners as decision trees can deal with new instances that arrive with more label classes. New instances can arrive with new headers.
2/ To change class labels dynamically, we need to add a method "setValue(int, string)" in the Attribute class to add dynamically new attribute values. 3/ The current design is being compatible with the methods in weka instances. It could be nice to have a fresher design. I will need some help to have a simplified and fresher design of the instances as I'm a bit conditioned by the previous instance usage :) Thanks, Albert On Wed, Jan 21, 2015 at 2:33 AM, Olivier Van Laere <[email protected]> wrote: > Hey Matthieu, > >> On Jan 20, 2015, at 1:47 AM, Matthieu Morel <[email protected]> wrote: >> >> I'm confused. From what I see the number of classes is currently fixed >> in the instance header. As if it was static. I suppose you can work >> around that limitation with some hacks but I want to use a clean API >> for that. >> >> Or is there a recommended way I'm missing? > > Ah, I think I remember now what happened. As far as I encountered this > situation, the data had say an .arff format with a header stating the number > of class values, and the instance header was read from that, while the > instances were then read by the line. > > I worked around that by just storing the class label seen in the instances on > the fly when building a model, and ignored that field of the instance header. > Sorry for the confusion! > > Cheers, > Olivier > >
