I'm trying to understand how the following .arff file can be expressed in Weka when loading data from database instead of the file. An .arff file has the following form:
@relation sample
@attribute expression string
@attribute tone {postive,negative}
@data
'this is a happy message', positive
'this is an unhappy message', negative
In the case of loading data from a database, consisting of one table with two fields - expression and tone - , how can I let weka know that the field tone gets only two possible values, positive or negative ?
Both of the fields are Strings. I want to apply NominalToString filter on expression to convert it to String and the apply StringToWord filter. However because of the tone attribute it can't be done... Any solutions?
I asked same question before. You may see detailed answer and necessary code in that question.
short answer : you merge correct arff header from external file with data from database.