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From |
Eric Booth <eric.a.booth@gmail.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: calculating cumulative values of other observations |

Date |
Fri, 6 Apr 2012 20:29:36 -0500 |

<> ******************! //input example data// clear inp ID str18 date str4 activity hours 1 20071230 A 10 1 20071122 A 11 2 20071120 A 5 3 20071210 B 6 3 20071111 B 24 3 20071130 F 20 3 20070511 B 49 4 20070611 A 50 end //cleanup// g date2 = date(date, "YMD") format date2 %td sort ID activity date2 //gen prior hours var// g priorhrs = 0 forval n = 1/`=_N' { by ID activity: replace priorhrs = /// priorhrs + hours[_n-`n'] /// if date2[_n]>=date2[_n-`n'] } l ********************! - Eric __ Eric A. Booth Public Policy Research Institute Texas A&M University ebooth@ppri.tamu.edu +979.845.6754 On Apr 6, 2012, at 6:09 PM, KOTa wrote: > Hi all, > > i have a data looking like this: > > ID date activity hours prior result should be: > 1 20071230 A 10 ? <-- 11 > 1 20071122 A 11 ? 0 > 2 20071120 A 5 ? 0 > 3 20071210 B 6 ? 73 > 3 20071111 B 24 ? 49 > 3 20071130 F 20 ? 0 > 3 20070511 B 49 ? 0 > 4 20070611 A 50 ? 0 > > (better picture here http://gyazo.com/5dc1218534d8b185ab22989069034b8a.png ) > > i need to fill "prior" column with following: > - amount of hours spent on same activity by same user(ID) prior to > date of current activity. > > example: > in case of observation 4(line 4) activity is B, so prior = sum of > hours spent on activity B before it took place (i.e. before 20071210) > there are 2 such observations, one with 49 hour, another with 24. > Therefore, prior = 24+49=73. > > > any suggestions how to make this simple? > > i was thinking to use "sort" and "by:", but i can't figure out how to > conditionally("if") sum up values from different observations into > "prior" var > its not a first time i encounter similar problem and always took some > way around, but this time i decided to ask, maybe there is proper, > simple way to do this > > thank you in advance > > K. > * > * 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/ * * 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: calculating cumulative values of other observations***From:*Nick Cox <njcoxstata@gmail.com>

**References**:**st: calculating cumulative values of other observations***From:*KOTa <kota.alba@gmail.com>

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