Why using "weka.filters.supervised.attribute.AttributeSelection" in Weka deletes the "@@class@@" attribute

Question

I am using Weka Explorer in data mining project, I have too many attributes and I want to reduce them by using Ranking in weka.filters.supervised.attribute.AttributeSelection but when I apply it the Attribute "@@Class@@" is deleted which is must be used in the classifier in next step !

Why attribute "@@Class@@" is deleted ? how to solve this problem ? Any suggestions?

Answer 1

Most likely you have not set the @@Class@@ attribute as the class when performing attribute selection. Ensure you are setting the appropriate class index using -c in the command line or void setClassIndex(int classIndex) in your Java code.