Hi, in an application I need to loop over various article data sets and to use the stack() function. However, currently stack() cannot be used within a loop. Alternative I was trying to use the <dataset addobs> command which is, however, explicitly not usebale within a loop: <hansl> set verbose off clear scalar r = 10 loop i=1..r -q open denmark.gdt -q -p series x = stack(L*) # "The symbol 'stack' is undefined" # dataset addobs 5 # does not work endloop </hansl> Is there an alternative way on how to stack variables within a loop? I was thinking to make use of "nulldata" for initializing a bigger data set, join the actual dataset which is big enough to allow for stacking. However, this requires that I know how big the initial data set has to be... Thanks, Artur