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From |
Michael McCulloch <mm@pinest.org> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: RE: creating expanded records with indicator variables, where different ID's reside in the same rows |

Date |
Wed, 21 Oct 2009 11:06:56 -0700 |

Thanks to Nick and Jeph and Martin. Here's a summary: 1. Nick's example works very well. 2. Jeph's example not allowing the -keep- statement, probably because I'm using v10. 3. I created a partial based on Martin's recommendation of -stack-; the lingering bug is what to do about records where both samples A and B are true for the same id, as in ID==11? * My solution ***** webuse stackxmpl, clear drop c d set obs 3 replace a=11 in 3 replace b=11 in 3 list stack a a b b, into(id) clear wide sort _stack drop if a==.&b==. replace a=1 if a!=. replace b=1 if b!=. replace a=0 if a==. replace b=0 if b==. sort id list id a b ***** * Nick's example ***** webuse stackxmpl, clear drop c d set obs 3 replace a=11 in 3 replace b=11 in 3 list gen long id = _n expand 2 if a != b bysort id : replace id = cond(_n == 1, a, b) replace a = a == id replace b = b == id l id a b ***** On Oct 21, 2009, at 10:52 AM, Nick Cox wrote: > OK. Try this: > > input a b > 5 5 > 6 11 > end > gen long id = _n > expand 2 if a != b > bysort id : replace id = cond(_n == 1, a, b) > replace a = a == id > replace b = b == id > l > > > Nick > n.j.cox@durham.ac.uk > > > -----Original Message----- > From: owner-statalist@hsphsun2.harvard.edu > [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Michael > McCulloch > Sent: 21 October 2009 18:21 > To: statalist@hsphsun2.harvard.edu > Subject: Re: st: RE: creating expanded records with indicator > variables, > where different ID's reside in the same rows > > Sorry Nick, yes you're correct, it should be: > id A B > 5 1 1 > 6 1 0 > 11 0 1 > Michael > > On Oct 21, 2009, at 10:18 AM, Nick Cox wrote: > >> Sorry, but I can't even follow your first two steps. Why isn't the >> second observation 6 1 0? >> >> Nick >> n.j.cox@durham.ac.uk >> >> Michael McCulloch >> >> I have a data structure that has been gathered as follows, where each >> cell contains the subject ID if A is true, and similarly for B. >> Therefore, for subject 5, I have A=yes and B=yes, whereas for >> subjects >> 6 and 11, only B=yes. >> >> A B >> 5 5 >> 6 11 >> >> I'd like to transform the data structure such that each row would >> have >> ID, and indicator variables for A and B. >> id A B >> 5 1 1 >> 6 0 1 >> 11 0 1 >> >> I've tried an approach like this, where I create indicator variables >> but A and B, but am not sure how to "expand" from the data structure >> where different ID's reside in the same rows. >> . gen id1=a >> . gen id2=b >> . gen aa=1 if a!=. >> . gen bb=1 if b!=. >> >> It also looks like -reshape- is not suitable because different ID's >> reside in the same rows. >> Any advice would be appreciated. > > * > * 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/ Michael McCulloch Pine Street Foundation 124 Pine Street San Anselmo, CA 94960-2674 tel: 415-407-1357 fax: 206-338-2391 mm@pinestreetfoundation.org * * 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**:**AW: st: RE: creating expanded records with indicator variables, where different ID's reside in the same rows***From:*"Martin Weiss" <martin.weiss1@gmx.de>

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