question: protected String instanceToLibsvm ( Instance inst ) { StringBuffer result ; int i ; result = new StringBuffer ( "" + inst . classValue ( ) ) ; for ( i = 0 ; i < inst . numAttributes ( ) ; i ++ ) { if ( i == inst . classIndex ( ) ) { continue ; } if ( inst . value ( i ) == 0 ) { continue ; } result . append ( " " + ( i + 1 ) + ":" + inst . value ( i ) ) ; } return result . toString ( ) ; }
target:  turns the instance into a libsvm row