Handling of missing variables

Hi all,

I am having some difficulties with handling missing values in my data. My dataset has questions marks (?) where there are missing values and I need an operator that will identify these as missing values and ignore them if possible? Does such an operator exist? I do not wish to replace these missing values with any other calculated values simply declare them as missing. It is important that I do not lose the entire row of data as there are 90 odd attributes in each row of data with some missing values throughout. I simply wish to ignore the individual cells with these ? in them. Any assistance in this matter will be greatly appreciated.

Regards,

Chris