Subset based on missing in differnet variables

#1
Suppose I have credit ratings for 5 years (credit1, credit2, credit3, credit4, credit5).
I only want to keep observations which have at least three non-missing credit scores of any combination. Is there a more efficient way to do this than using rbind?

Thank you!
 

vinux

Dark Knight
#2
Suppose I have credit ratings for 5 years (credit1, credit2, credit3, credit4, credit5).
I only want to keep observations which have at least three non-missing credit scores of any combination. Is there a more efficient way to do this than using rbind?

Thank you!
Do you mind posting an example?