Hi Sebastian, if classes/labels are the same for both training and test, that should not be a problem. I've done that and never seen any issues. As far as I can see, scikit learn automatically maps classes into numbers from 0 to number of classes -1, which is something Spark, for example, does not do.
With different set of classes, the simplest thing is to remove the ones in the test that do not appear in the training, to avoid messing with the confusion matrix [ in my case, different label numbers are really different classes ] ________________________________________ From: Sebastian Raschka [se.rasc...@gmail.com] Sent: Thursday, April 30, 2015 11:08 PM To: scikit-learn-general@lists.sourceforge.net Subject: Re: [Scikit-learn-general] class label hashing Roberto, I am not sure if this causes problems regarding the implementation, but in any case, I'd recommend you to use the LabelEncoder to have your classes mapped to a fixed range, e.g., 0, 1, 2, 3, 4, 5. And having different class labels in training and test set that reference to the same class is not good practice and could cause all kinds of problems. I just wouldn't risk it even it it works. > On Apr 30, 2015, at 11:02 PM, Pagliari, Roberto <rpagli...@appcomsci.com> > wrote: > > Suppose I train a classifier with dataset1, which contains labels > > 0 > 3 > 4 > 6 > 7 > > and then predict over dataset2 with labels > > 0 > 3 > 4 > 8 > 10 > > will the hashing be the same for labels 0, 3 and 4? and will scikit learn get > confused by seeing new labels such as 8 and 10? > > Thank you, > > ------------------------------------------------------------------------------ > One dashboard for servers and applications across Physical-Virtual-Cloud > Widest out-of-the-box monitoring support with 50+ applications > Performance metrics, stats and reports that give you Actionable Insights > Deep dive visibility with transaction tracing using APM Insight. > http://ad.doubleclick.net/ddm/clk/290420510;117567292;y_______________________________________________ > Scikit-learn-general mailing list > Scikit-learn-general@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/scikit-learn-general ------------------------------------------------------------------------------ One dashboard for servers and applications across Physical-Virtual-Cloud Widest out-of-the-box monitoring support with 50+ applications Performance metrics, stats and reports that give you Actionable Insights Deep dive visibility with transaction tracing using APM Insight. http://ad.doubleclick.net/ddm/clk/290420510;117567292;y _______________________________________________ Scikit-learn-general mailing list Scikit-learn-general@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/scikit-learn-general ------------------------------------------------------------------------------ One dashboard for servers and applications across Physical-Virtual-Cloud Widest out-of-the-box monitoring support with 50+ applications Performance metrics, stats and reports that give you Actionable Insights Deep dive visibility with transaction tracing using APM Insight. http://ad.doubleclick.net/ddm/clk/290420510;117567292;y _______________________________________________ Scikit-learn-general mailing list Scikit-learn-general@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/scikit-learn-general
