Re: st: Invalid file specification

[Michael Hanson <mshanson@mac.com>]

On Jul 7, 2007, at 5:09 AM, Hendri Adriaens wrote:

> I'm trying to do something for several files, using a loop. But  
> somehow, it
> doesn't work and the error message "invalid file specification"  
> doesn't
> really help.
>
> #delimit;
> forvalues x=1/4 {;
>   if `x'==1 {local bestand="parsed_cfd.txt"; local zk="cfd";};
>   if `x'==2 {local bestand="parsed_qds.txt"; local zk="qds";};
>   if `x'==3 {local bestand="parsed_vfd.txt"; local zk="vfd";};
>   if `x'==4 {local bestand="parsed_tsa.txt"; local zk="tsa";};
>
>   #delimit;
>   clear;
>   /* Inlezen */
>   insheet a b c d e using "`bestand'", tab;
>
> [some more commands]
>
> };
	I find that most Stata expressions that appear to require an -if-  
statement (as opposed to the -if- qualifier) can be transformed into  
something that does not, and it usually works better as well.  In  
your case, one possibility would be something like (note: untested!):

local zklist "cfd qds vfd tsa"
foreach zk of local zklist {
    clear
    insheet a b c d e using "parsed_`zk'.txt", tab        // Inlezen

    [some more commands]
}

Notes:

	1. My personal preference is to use the perfectly fine carriage  
return delimiter, rather than littering one's code with semicolons;   
arguably in your case the use of -#delimit;- made it more difficult  
to find your error.

	2. You don't say what "[some more commands]" constitutes, but if you  
don't need "x" later (which the above code presumes), then it's just  
more overhead that (empirically) can lead to potential errors.

	3. If you do not need the "bestand" local macro later, then you can  
follow the suggested code above.  Otherwise, within the loop you can  
create a local macro as

local bestand = "parsed_`zk'.txt"

	4. It isn't clear to me that your -if- statements are literally  
invalid Stata code:  they merely did not return the values you  
intended ("bestand" appears to have not been defined), which then led  
to problems down-stream.  But I doubt any error reporting convention  
would have been able to identify your specific problem -- and the  
suggestions of Austin & Kit on debugging are worth following.

	Hope this helps.

                                        -- Mike


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