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javaexceptioninstanceweka

problem in using weka.core.instance in java

i have a trained j48 classifier and i want to classify one record by it. so i decided to use weka.core.instance object and classify it by command : "classifyInstance(record)"/ but i have a problem in at first step: creating instance. when i want to set the values of attributes i get exception : Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: -1 i have 24 attribute which first of them is string and others are int. so i use the code below:

    Instance record = new Instance(data.size());
    for(int i=1; i<data.size(); i++) 
    record.setValue(new Attribute(featuers[i]), Integer.parseInt(data.get(i)));

data is a arrayList which contains the value of attribute and featuers is a String Array that contains name of attributes.

thanks alot.

Solution

  • for String or nominal attributes, first we should add the value of string attribute to dataset and then try to setValue for instance.