Re: st: RE: -replace- should not be use with temporary files (was: Comparing datasets)

[Steven Samuels <sjhsamuels@earthlink.net>]

Joseph Coveny wrote:
> This is news to me.  I use -replace- all of the time with temporary
> files. What did StataCorp technical support say was the matter with  
> using
> -save . . . , replace- with temporary files?
>
>
> > Steven Samuels wrote (excerpted):
> >
> > . . . Technical support told me that "replace" should not be used  
> > when
> > saving temporary files.
Joseph

What happened was--I tried to save a temporary file `t2',  without  
first defining it  Stata did not issue an error message, and I had no  
clue as to where I'd gone wrong. (My only excuse-I was tired.)  Kerry  
Kammire of StataCorp pointed out my error and went on to say that  
there were actually two syntax errors.

"The second syntax error -save, replace- prevented Stata from issuing  
an error
when `t2' is undefined. The -replace- option shouldn't be needed when  
using
temporary files because they are freshly created each time the  
procedure is
run."

Thus -replace- was unnecessary and, in this case, harmful.

-Steve

On Sep 18, 2008, at 12:22 PM, Nick Cox wrote:


> This came up on the list a while back.
>
> Suppose you mistype the local macro reference. Say you mean to type
>
> save `myfile', replace
>
> but you have a minute brainstorm and you type `myfil'. Further suppose
> that local macro `myfil' is not defined. Then Stata sees
>
> save, replace
>
> which to Stata is perfectly legal and intelligible. Stata will  
> overwrite
> the original data file, which is not what you intended at all. Of
> course, typos here and there can have all sorts of consequences,  
> all of
> which are strictly your fault, but this one could be catastrophic if
> what you had in memory was only a small part of the data or nothing to
> do with the dataset you last read in.
>
> There may be other reasons for not doing this, but that's one.
>
> Nick
> n.j.cox@durham.ac.uk
>
> Joseph Coveney
>
>
>
> *
> *   For searches and help try:
> *   http://www.stata.com/help.cgi?search
> *   http://www.stata.com/support/statalist/faq
> *   http://www.ats.ucla.edu/stat/stata/
*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/