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feelinginwind 发表于 2010-4-6 05:58 thanks. the sum() gives the total but not accumulative sum for each period.
feelinginwind 发表于 2010-4-8 22:51 for a long data, use sum() has to control the id for longitudinal data. how to control the id here?
htslchy 发表于 2010-4-24 18:28 egen s=sum(x) 即可