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From |
Ulrich Kohler <kohler@wz-berlin.de> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: create a variable based on a recurring value in a varlist |

Date |
Thu, 13 Oct 2005 09:43:48 +0200 |

Derek Darves wrote: > I have a group of variables: > > PID1 - PID15 > > PID* takes on values from 1 to 8000, and many are missing. > > Basically, I would like to make a new variable, called interlock, > that is equal to 1 if any of the variables in the list are equal to > any other variable in the list (not including itself, of course). > For example, if PID5==705 and PID14==705 I would like like interlock==1 > > Likewise, if none of the the variables in PID* take on the value of > any of the other variables in PID*, I would like interlock==0 > > I tried this: > egen interlock = group(pid1_a pid1_b pid2_a pid2_b pid3_a > pid3_b pid4_a pid4_b pid5_a pid5_b pid6_a pid6_b pid7_a > pid7_b pid8_a pid8_b pid9_a pid9_b pid10_a pid10_b pid11_a > pid11_b pid12_a pid12_b pid13_a pid13_b pid14_a pid14_b pid15_a) > > , but it returned all missing values when I know that some share a > common value in two of the PID* fields. > > Lastly, not that it should matter, but the above is a simplifying > example. In my actual dataset I have about 130 PID* variables. I just > mention this in case I am hitting some kind of memory limitation (I > am not receiving any errors when I run the command, though, it just > doesn't work). There might be easier solutions, but I always think reshape-by: ---------------------------------------------- // Preparations for easy reshape local i 1 foreach var of varlist pid* { ren `var' pid`i++' } gen index = _n // Solution for Problem reshape long pid, i(index) j(var) by index (pid), sort: gen same = sum(pid==pid[_n-1]) by index: replace same = same[_N] >= 1 reshape wide ------------------------------------------------ . by by Uli -- kohler@wz-berlin.de +49 (030) 25491-361 * * For searches and help try: * http://www.stata.com/support/faqs/res/findit.html * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**References**:**st: create a variable based on a recurring value in a varlist***From:*Derek Darves <darves@uoregon.edu>

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