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Re: st: How to quickly merge by the range of a third variable?
Thanks Taavi; before your hint I didn't even think of merging by two
On 10/10/05, Taavi Lai <email@example.com> wrote:
> Maybe there is a better way to do it but I would generate one dataset
> containing all the B-s and correstponding year by -append- and did the
> -merge- using this composite file by variables id and year. sth like
> use b1, clear
> gen year==1900
> save b_comp, replace
> use b2, clear
> gen year==1901
> append using b_comp
> save b_comp, replace
> use a, clear
> merge year id using b_comp
> And you could use looping for the first part but as I'm not proficent
> with it so I'd better leave it for other list members
> Best regards
> Sean wrote:
> >Dear Statalisters,
> >I have a quick question about how to speed up the merging process.
> >Suppose I have one A dataset and several B dataset, denoted as B1, B2, B3, etc.
> >In A dataset, I have individuals' id numbers along with his/her birth
> >city and birth year. Now in B's datasets, it stores the information of
> >all the cities in a particular year, such as B1: all the cities for
> >year 1, B2: all the cities for year2, B3 for year3, etc. For example,
> >in year 1, I can get every city's population size for that year.
> >Now my goal is to get each individual's birth city population size, of
> >course, for that particular year when the individual was born. To
> >summarize, in dataset A, I have the following variables:
> >id birthyear birthcity
> >in B's datasets, I have
> >cityid population
> >I am aware that I should merge the right B dataset with A through
> >city, however, which year when the individual was born determines
> >which B dataset I should merge for that observation. I didn't find by:
> >or if... conditional command for "merge", as I imagined.
> >Is there a quickest way to finish this mission?
> >Thanks all.
> >* 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/
> * 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/
* For searches and help try: