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From | Maarten Buis <maartenlbuis@gmail.com> |
To | statalist@hsphsun2.harvard.edu |
Subject | Re: st: Two dichotomous variables to One Categorical |
Date | Fri, 12 Oct 2012 10:22:54 +0200 |
On Fri, Oct 12, 2012 at 10:07 AM, malay biswas wrote: > I am trying to transform my two dichotomus variables (Present/Absent, > Present/Absent) into one categorical variable depending upon four > configurations(Present Present =1, Present Absent=2, Absent Present=3, > Absent Absent=4). There are several solutions possible, the one I currently use most is. gen newvar = cond(var1==1, /// cond(var2==1, 1, 2), /// cond(var2==1, 3, 4) ) /// if !missing(var1,var2) The idea is that the -cond()- function contains three parts: cond(expression, what happens when expression is true, what happens when expression is false). So the first cond() separates between var1 == 1 and var1 != 1; the second cond() separates var2 when var1 == 1; the third cond() separates var2 when var1 != 1, and finally the !missing(var1,var2) part takes care of missing values in var1 and var2. You can also look at -egen group-. Hope this helps, Maarten -- --------------------------------- Maarten L. Buis WZB Reichpietschufer 50 10785 Berlin Germany http://www.maartenbuis.nl --------------------------------- * * 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/