[Gretl-devel] Re: Stringified series cannot be over-written
Am 04.12.19 um 23:19 schrieb Allin Cottrell:
On Wed, 4 Dec 2019, Artur Tarassow wrote:
> I am bit puzzled why one cannot assign new values to a stringified
> series (using current git). Why should be the behavior differently
> compared to numerical series?
>
> <hansl>
> set verbose off
> nulldata 2
>
> series foo = seq(1,2)'
> strings s = defarray("A", "B")
> stringify(foo, s)
> print foo
>
> series foo = 1 # "Cannot overwrite entire string-valued series
</hansl>
Well, the intent is to preserve the integrity of such series. We
obviously couldn't have anything like series foo = log(foo) and still
have a string-valued series.
Ok, I understand this. Thanks.
In the case of assigning a scalar value (that's within the range
of
the existing encodings) to the entire series, as above, no harm would
be done.
The question then is whether we just issue a blanket ban on assigning
to an entire string-valued series (the case at present), or take the
trouble to code an observation-by-observation check on the validity of
such an assignment.
What about a compromise that for a string-valued series one
cannot
change separate entries but assigning a complete new value, e.g. by
doing <series foo = 1>, is allowed? I was think of something like:
<>
series y = normal()
series foo = seq(1,2)'
strings s = defarray("A", "B")
stringify(foo, s)
foo[1] = "C" # not allowed
series foo = 99 # allowed
series foo = y # allowed as y is of same length as foo
</>
This would avoid the obs-by-obs check on the validity -- at least I
guess so.
We could do the latter but it didn't seem worthwhile to me when
we
first introduced such series. It wasn't clear to me that there was any
real use case -- do you have one?
I have a really huge panel data set ( > 4GB) and run multiple
estimations by means of a loop-block. Each round I export some list of
series and want to construct a series "foo" holding some round-specific
string value(s). Currently, I need to generate each round some new
series "foo_$i$. I have not found an alternative way to avoid the
construction of an additional series every round. Of course each
additional series blows up memory demand.
As deleting a series within a loop-block is also not allowed, I could
not think of an alternative solution to this.
Thanks,
Artur