Dear all, I am working with panel data and I want to run a loop with time dummies. Unfortunately, I encounter a problem when trying to do so. loop i=1..4 # this loop needs to be performed 4 times     genr k=($i*12)     genr Z=k-11     matrix Big=zeros(25,14)     list R= dt_$Z..dt_$k     scalar j=0     loop foreach x R         smpl $x --dummy Here is the first part of my script where things go wrong. I need to make the list R 4 times. First with dt_1 to dt_12, in the second loop from dt_13 to dt_24 and so. After running this script Gretl returns the error value: ? list R= dt_$Z..dt_$k The symbol 'dt_' is undefined >> list R= dt_$Z..dt_$k When I run the following script I get the right values for k and Z but they have 6decimal digits (0's) (for instance Z=1,000000 instead of 1): loop i=1..4 # this loop needs to be performed 4 times genr k=($i*12) genr Z=k-11 print k Z endloop Therefore I assume that the problem is that Gretl does not recognize dt_1,000000. I tried to use the function int() and round() to get rid off those decimal digits but these functions did not help. Is there any other solution to get rid off the decimal digits so that Gretl gets as input dt_$Z = dt_1 instead of dt_1,000000? Many thanks in advance. Best regards, Kevin Vermeiren _______________________________________________ Gretl-users mailing list Gretl-users(a)lists.wfu.edu http://lists.wfu.edu/mailman/listinfo/gretl-users

You can use string variables to hold the names of the starting and ending series in the list, and use "@" to invoke string substitution: loop i=1..4 -q scalar k = i*12 sprintf lmax "dt_%d", k sprintf lmin "dt_%d", k-11 list R = @lmin..@lmax list R print endloop