Attribute type problem

[braverju]

Hi everybody,

I am very new on Weka and would appreciate your help very much. I have a data file in a csv format. When I open it in Weka it claims some variable to be Nominal, despite they are Numerical. It happens because of the missing values. In my csv files those are empty cells, but Weka converts them to "-". I tried to code missing values to be 9999. Then, Weka claims the right Numerical type, but does not allow to
change or delete these cells. What is the solution?

Thank you vey much
Julia

[fracpete]

Instead of using 9999 for missing values, use ? (= question mark) in your data. That should do the trick, when importing data with the CSVLoader (or choosing "CSV files" in the Explorer).

[braverju]

Yes. It really does the trick. Thank you for the answer, although, a bit late. I've figured it out about 6 weeks ago. :)) I am sorry for not updating my post. Hopefully, it will help to somebody else.