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From |
Nick Cox <njcoxstata@gmail.com> |

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

Subject |
Re: st: Merging consecutive spells with the same value of Y |

Date |
Mon, 17 Jun 2013 11:29:56 +0100 |

Assuming no gaps bysort ID (Start) : gen Spell = sum(Y != Y[_n-1]) collapse (min)Start (max)End Y, by(ID Spell) Nick njcoxstata@gmail.com On 17 June 2013 11:07, Kai Huang <demonsecret@hotmail.com.hk> wrote: > Dear all, > > I have a spell dataset as follows: > > ID Start End Y > 888 1981 1985 0 > 888 1985 1989 2 > 888 1989 1991 1 > 888 1991 1995 1 > 888 1995 1997 1 > 888 1997 2000 2 > 890 1985 1987 2 > 890 1987 1991 0 > 890 1991 1994 0 > 890 1994 1997 1 > I hope to merge consecutive spells with the same value of Y, so that the data becomes as follows: > ID Start End Y > 888 1981 1985 0 > 888 1985 1989 2 > 888 1989 1997 1 > 888 1997 2000 2 > 890 1985 1987 2 > 890 1987 1994 0 > 890 1994 1997 1 > > I use the following commands, but can only achieve my aim for ID 890: > by ID: replace End = End[_n+1] if EconActivity==0 & EconActivity[_n+1]==0 > by ID: drop if End == End[_n-1] & Start>Start[_n-1] & EconActivity==EconActivity[_n-1]==0 > by ID: replace End = End[_n+1] if EconActivity==1 & EconActivity[_n+1]==1 > by ID: drop if End == End[_n-1] & Start>Start[_n-1] & EconActivity==EconActivity[_n-1]==1 > > I wonder how I can merge all consecutive spells with the same value of Y, even if the number of consecutive spells are more than 2? Thank you very much in advance. > > Best regards, > Kai Huang > * > * 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/ * * 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/

**References**:**st: Merging consecutive spells with the same value of Y***From:*Kai Huang <demonsecret@hotmail.com.hk>

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