Re: st: Structure for making line by line changes?

[Fred Wolfe <fwolfe@arthritis-research.org>]

At 12:06 PM 4/25/2003 -0700, you wrote:
> Hello,
>
> I am very new to Stata and am having some difficulty wrapping my brain 
> around Stata's methods of data processing. I would like to be able to 
> process a dataset line by line rather then all at once. I have found many 
> references to the fact that "if" statements don't work as expected and a 
> very good comparison between STATA and SAS which briefly mentions some of 
> the paradigm shifts.
>
> My question to the group is how would you deal with the line by line 
> processing issue? I need to change each line based on a calulated value 
> that is dependant upon data in that line.
>
> The "if" qualifier would seem to solve this for some cases, but not when a 
> program has to be called or a really complex comparison has to be done.

Nick's reply is to indicate that you really don't need to loop over 
observations. People coming from SAS very often think that you do. Using 
Stata, in some instances you might need to create an intermediate variable. 
Following up on Nick's reply, we have a problem thinking of cases where you 
really need to do it the way you suggest. Perhaps a specific example would 
clarify your problem for us.

Fred Wolfe



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Fred Wolfe                                                          Tel 
(316) 263-2125
National Data Bank for Rheumatic Diseases         Fax (316) 263-0761
Wichita, 
Kansas                                    fwolfe@arthritis-research.org
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