[Gretl-users] Re: series indexing

On Fri, 11 Sep 2020, Riccardo (Jack) Lucchetti wrote: > A user wrote me in private, asking me about some oddities on series > indexing via strings. I put together a little example: > > <hansl> > nulldata 4 > xs = normal(2,1) > setobs 1 2000 --time-series > > # 1: this works > xs["2000"] = 3 > # 2: this works too > a = sprintf("\"2000\"") > xs[@a] = 33 > # 3: this doesn't > a = "2000" > xs[a] = 33 > </hansl> > > if assignments 1 and 2 work, one sees no reason why 3 shouldn't work too. > Or ami I missing something obvious? Well, when indexing into a series gretl expects one of the following: * a literal observation-marker string * an integer (1-based) observation number * an expression which evaluates to an observation number That's fairly flexible. But if we get a variable as an index we try to interpret it as a plain integer, which obviously doesn't work for a = "2000". Note that these work [...]