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From | Joseph Luchman <jluchman@gmail.com> |
To | statalist@hsphsun2.harvard.edu |
Subject | RE: re: st: Package -r2c- now available in SSC |
Date | Wed, 6 Feb 2013 08:19:54 -0500 |
Hello Nick and Maarten, I agree with Simon - thank you for the suggestions. I realize that such variable names are likely to appeal to the users of count data models (no doubt for the same reason they appealed to me as names). I can assure (potential) users of -r2c- that a safeguard is built into the program however to avoid overwriting variables (the data are preserved before dropping and generating, then subsequently restored before the program terminates). The program generates a variable in the dataset to refer to it in different programs within the command so that it will not be dropped at the generating command's termination, which is also why global macros are dispersed throughout instead of local ones (I originally wanted to use tempvars and, in fact, do within any one program when it makes sense to do so). The approach is a little "clunky" and inelegant; this issue is something I plan to fix in future renditions of the command. I'll admit that I'm mainly familiar with the capabilities of Stata 12 (the version I mainly learned Stata on). I added the version 12 requirement so that I could be sure all the facilities I take for granted in 12 will work, and so it's not a good answer as to why it's only useful for 12 at current - mostly a function of my ignorance of the capabilities of versions 11, 10, and earlier and how they overlap with version 12. In the end, I would like to make the command backwards compatible and I intend to do so as soon as I can for interested users as I anticipate that it does not use many (or perhaps any) facilities that are new to version 12. Please do forward on any other problems discovered or suggestions for the -r2c- command and I appreciate the dialog regarding the command. - joe Joseph Nicholas Luchman, M.A. ---- Senior Research Associate | Fors Marsh Group Desk: 571 858 3770 Email: jluchman@forsmarshgroup.com forsmarshgroup.com ---- Doctoral Candidate Industrial Organizational Psychology George Mason University http://sites.google.com/site/jluchman/ Thanks Nick and Maarten for your insights on the -r2c-. Very good comments and suggestions. Simon -----Original Message----- From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Maarten Buis Sent: den 5 februari 2013 20:38 To: statalist@hsphsun2.harvard.edu Subject: Re: re: st: Package -r2c- now available in SSC On Tue, Feb 5, 2013 at 7:46 PM, Nick Cox wrote: > I note in passing that -r2c- evidently feels free to use the variable > names > > mu mumean wt _est_full counts alpha > > so that it will -drop- any previous instances and then overwrite them > with new ones. This is not documented so far as I can see. Correct me > if I am wrong, such practices are widely regarded as dangerous Stata > programming style. Some of these names look highly likely to appeal to > people fitting count models. To add to this: the typical way in which this is circumvented is to use temporary variables. So you would do something like: tempvar mu mumean wt _est_full counts alpha gen `mu' = ... egen `mumean' = ... etc. the variables `mu' , `mumean', etc. (notice the -`- and the -'-, they are necesary) will have unique names that do not exist in your data, they will exist as long as the program runs and will be deleated when the program ends. That way you do not change the data (unless the user explicitly asks for it), which is typically considerd good practice in this community. -- Maarten --------------------------------- Maarten L. Buis WZB Reichpietschufer 50 10785 Berlin Germany -------------------------------- * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/faqs/resources/statalist-faq/ * http://www.ats.ucla.edu/stat/stata/