Creating and saving an Attribute-Relation File Format (ARFF) file

Weka's native file format is called Attribute-Relation File Format (ARFF). There are two logical parts of an ARFF file. The first part is called header, and the second part is called data . The header part has three physical sections that must be present in an ARFF file--the name of the relation, the attributes or features, and their data types and ranges. The data part has one physical section that must also be present to generate a machine-learning model. The header part of an ARFF file looks like the following:

% 1. Title: Iris Plants Database 
   % 
   % 2. Sources: 
   %      (a) Creator: R.A. Fisher 
   %      (b) Donor: Michael Marshall (MARSHALL%[email protected]) 
   %      (c) Date: July, 1988 
   % 
   @RELATION iris 
 
   @ATTRIBUTE sepallength     NUMERIC 
   @ATTRIBUTE sepalwidth      NUMERIC 
   @ATTRIBUTE petallength     NUMERIC 
   @ATTRIBUTE petalwidth      NUMERIC 
   @ATTRIBUTE class  {Iris-setosa...