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From |
"Nick Cox" <n.j.cox@durham.ac.uk> |

To |
<statalist@hsphsun2.harvard.edu> |

Subject |
RE: st: Create a new variable based on some other variables |

Date |
Thu, 21 May 2009 11:39:34 +0100 |

Let's spell out that there is a difference between gen B = cond(A1 == 1, 1, cond(A2 == 3, 2, cond(A3 == 8, 3, 0))) and gen B=(A1==1)*1 + (A2==3)*2+(A3==8)*3 The order in -cond()- is crucial. Once for example observations with A1 == 1 are dealt with, they are not revisited, regardless of whether A2 == 3 or A3 == 8 in the same observation. Nick n.j.cox@durham.ac.uk Martin Weiss I thought about this case as well. If Charles wants the values for "B" to accumulate, the solution is simply *** gen B=(A1==1)*1+/* */(A2==3)*2+(A3==8)*3 *** From: "Nick Cox" <n.j.cox@durham.ac.uk> > Thanks for the oblique compliment, but -cond()- is an official Stata > function. My only indirect contribution, some while ago, was to suggest > it being generalised so that it could also produce string results. > > The article referred to by Martin Weiss at > http://www.stata-journal.com/sjpdf.html?articlenum=pr0016 > was first-authored by David Kantor. > > However, there remains a problem with your specification. What happens > (e.g.) if a1 is 1 AND a3 is 8? > > Nick > n.j.cox@durham.ac.uk > > Charles Man@CCR > > Thanks to Martin and Eric for showing me how to do this and introducing > Dr Cox's -cond()- to me. Thanks a lot. > > From: "Eric A. Booth" <ebooth@ppri.tamu.edu> > >> gen b =. >> replace b=1 if a1==1 >> replace b=2 if a2==3 >> replace b=3 if a3==8 > >> On May 20, 2009, at 1:56 PM, Charles Man@CCR wrote: > >> > If I want to create a new variable based on the values of a few >> > other variables, how can I do that? >> > >> > For instance, >> > >> > Create B >> > If A1=1, then B=1 >> > If A2=3, then B=2 >> > If A3=8, then B=3 >> > >> > Can -gen- or -egen- or -recode- do this job? > * * 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/

**Follow-Ups**:**Re: st: Create a new variable based on some other variables***From:*"Martin Weiss" <martin.weiss1@gmx.de>

**References**:**RE: st: Create a new variable based on some other variables***From:*"Nick Cox" <n.j.cox@durham.ac.uk>

**Re: st: Create a new variable based on some other variables***From:*"Martin Weiss" <martin.weiss1@gmx.de>

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