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

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

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

Date |
Thu, 13 Oct 2005 12:43:00 +0100 |

This is easier done long. save safecopy gen long id = _n reshape long PID, i(id) bysort id (PID) : gen same = PID == PID[_n-1] bysort id (same) : replace same = same[_N] reshape wide Nick n.j.cox@durham.ac.uk Seb Buechte > you could take a "brute force" approach by comparing each var with all > the other vars using two loops: > > gen interlock=0 > foreach var1 of varlist PID1 PID2 .... { > foreach var2 of varlist PID2 PID3.... { > if "`var1'"!="`var2'" { // making sure you do not compare the > var with itself > replace interlock=1 if `var1' == `var2' > } > } > } > > I am not too sure how long it will take to run through these loops. Derek Darves > > 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). * * 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/

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

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