Dear Gretlers, I would like to know how to do two specific operations which I am not able to perform in a proper way: 1) delete variables using loop/for constructs 2) remove variables which contain only missing values and/or have less than "N" valid observations 1) As far as the first problem is concerned, I partially solved it by writing a file using outfile and printf but I guess it is not the most efficient way to do it. That is, for the time being I solved it in the following way: loop for (i=1; i<100; i+=1) However, I cannot directly use something like this: loop for (i=1; i<100; i+=1) because I receive the following error message: "You cannot delete series in this context" . 2) Besides the problem at point 1), I would like to know if there is a way to delete variables using some sort of condition upon the number of observations they contain. That is, what I have in mind is something like this (N is a scalar): loop for (v=1; v<100; v+=1) However, I cannot do it because if I run "missing($v)" inside a loop it interprets "$v" as a number and not as a reference to a variable. Therefore, I would like to know if there is any way to tell Gretl "consider that number as a reference to a variable, not as a scalar" since this would come handy also in many other situations. Notice also that, in my case, I cannot build a list containing all the (string) names of all the variables since I get an error (probably because Gretl cannot handle two thousands strings... I guess..). Thanks in advance for your help, Matteo