[Gretl-users] Re: Check whether a series defines a panel dimension

On Sun, 8 Sep 2019, Artur Tarassow wrote: > Hi all, > > for some function I need to check whether the passed series > corresponds to the variable defining the cross-sectional dimension of > a panel dataset. [...] > Do you some other ideas? If the variable in question is guaranteed to be discrete, you could use this: <hansl> function scalar is_crossdim_index_series(series x)     ret = isdiscrete(x)     if !ret         return ret     endif     matrix H = mxtab(x, $unit) .> 0     # check for 1-to-1 correspondence     chk = sumr(H) | sumc(H)'     ret = (maxc(chk) == 1) && (minc(chk) == 1)     return ret end function # example open abdata.gdt --quiet eval is_crossdim_index_series(YEAR) discrete unit eval is_crossdim_index_series(unit) </hansl>