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nlpweka

class index differ error in weka

I want to do text classification with weka. I have a train and a test file (Persian language). first I load the train file and then choose "string to word vector" in preprocess. And because of choosing that, the class position goes to the start. For moving the class to its index (which is 2 in the files), I can go either to "Edit" part and right click on the class column and choose "attribute as class" or just in classify menu, choose (NOM)class. (unless most of the algorithms would be inactive). I run SMO and save the model. The problem is, after opening the test file, and click on "re-evaluate the model on current test set", this error occurs that, "...class index differ: 1!=2". I know it is because after opening the test file, again the class column goes to the start. For train part I solved the problem as I described above. But how can I solve it for the test part, too?

sample train file: enter image description here

sample test file: enter image description here

Solution

  • First, I changed the files to vector based on 1000 most frequent words in train file and made a numeric arff file for the train and test file, then for both of them in the "classify" menu in "Test options" I chose "(Nom) class.