Hi Muna, 

Your question is not so accurate as you need to identify whether the attributes you mentioned are regular attributes or class attributes. If those attribute are regular ones, converting them is not necessary as it depends on the algorithm or the the task itself. On the other hand, for classification purposes, if your class attribute has 0 or 1 values, then converting this class into a nominal type is required.

HTH.

Samer

In Weka, a binary attribute is simply declared in the header as a nominal attribute with 2 values  Examples: Class {0, 1}, Married {Y, N}

There is a special approach for sparse files where you can not explicitly represent the 0 value.

More information at: http://www.cs.waikato.ac.nz/ml/weka/arff.html

Yes you can use both the 0 1 and Y N  in that. Weka provides a specific input format you need to convert your variables and their values into it.

Mr. Samer, thank you for your answer.

Indeed, my question is not about class but for attributes values which may have values like {Y/N, NIN, Y/Y N/Y}, how can I deal with? I can insert them directly into Weka tool or I must convert them to another format. 

Mr. Eduardo Corrêa Gonçalves.

Thanks for your answer, but I am not talking about class values, I mean attributes " features" values which have values such as Y/N, N/Y, Y/Y ...etc  

Ms. Muna,

Your question becomes clear now after editing process that you've done recently, and the clarification in your reply as well.

However, if you have such nominal attributes, then you can load them into WEKA directly.

Please let me know if you still have further issues.

HTH.

Samer

 Mr. Ali,  thanks for your answer, but I don't get it, can explain it more or can you send any tutorial or document for this issue, please. 

A lot of thanks Mr. Samer 

I learnt weka tool from here, these lectures are very useful.

https://www.youtube.com/watch?v=Fg2x_zM3YTo&list=PLzVF1nAqI9VmC96TbvOPMkXToSmBMHJn7