Re: st: tempfile & scope

[Nicholas Winter <nw53@cornell.edu>]

At 07:14 PM 9/24/2003 -0400, you wrote:
> Hi,
>
> Suppose I want to create 2 temporary datasets inside a -forval- loop, with
> names indexed by the loop number (i.e., `results0', `results1'). Once I get
> outside the loop, I want to append them using -dsconcat-, but since I
> defined them inside the loop, they no longer exist.
>
> A more concrete example:
>
> forval k = 0(1)1 {
>
>     tempname memhold
>     tempfile results
>
>     postfile `memhold' var1 var2 var3 using `results'`k', replace
>
>     forval y = 1998(1)2002 {
>         ...
>
>         post `memhold' (`x') (`y') (`z')
>     }
>
>     postclose `memhold'
> }
>
> dsconcat `results0' `results1'
>
> Could someone offer a suggestion on how to do this, please? Much thanks.
I think this isn't a scope problem, but a local macro naming issue.  I 
think you need to modify the way you get and use the -tempfiles-.

Currently in the loop you do:

        tempfile results

then you post to a file called `results'`k' , which will be the name of the 
-tempfile- Stata gave you, with the number 0 or 1 appended.  That might or 
might not even be a legal filename on your OS.  Then outside your loop, you 
refer to the locals `results0' and `results1' -- you never defined those 
locals.

Instead, your tempfile command should read:

        tempfile results`k'

On the first iteration, this will create a local macro called `results0'; 
on the second iteration it will create `results1'.

So inside the loop, post to `results`k''

Then at the end, after the loop, you can refer to `results0' and `results1'.

By the way, I'm not clear why you need the -tempname- for the posting 
defined repeatedly; you could just define one outside the loop, and reuse 
it repeatedly.


--Nick Winter







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