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From |
"Eric G. Wruck" <ewruck@econalytics.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: Re: new variable from 2 datasets |

Date |
Sat, 12 Nov 2005 14:31:06 -0500 |

I don't think that'll work, Friedrich, since Wanli says the variable names are the same in both files. Now if he (perhaps a she -- je ne sais pas) knows that each data set has the same ten variables & each has N observations, then something like this would be possible: use dataset1.dta, clear append datatset2.dta foreach var of varlist ....{ replace `var' = `var' - `var'[_n - N] if _n > N } Or to put it more concretely in terms of an example, assume dataset1 has variables x & y & dataset2 the same variables; each has four observations. After appending, +-------+ | x y | |-------| | 1 2 | | 2 3 | | 3 4 | | 4 5 | | 1 2 | |-------| | 2 3 | | 3 3 | | 4 5 | +-------+ . foreach var of varlist x y { 2. replace `var' = `var' - `var'[_n - 4] if _n > 4 3. } (4 real changes made) (4 real changes made) . l, noobs +--------+ | x y | |--------| | 1 2 | | 2 3 | | 3 4 | | 4 5 | | 0 0 | |--------| | 0 0 | | 0 -1 | | 0 0 | +--------+ If the data sets were identical, observations 5-8 would contain all zeros -- not the case here. I haven't given any thought to string variables, but undoubtedly something quasi-similar could be done for them. Hope this helps, Eric >Wanli, > >Rename the variables in one file, merge the data and then calculate >the difference. > >Friedrich Huebler > >--- Wanli Zhao <zhaowl@temple.edu> wrote: >> I have 2 datasets. Each one has 10 variables and they share the >> same names >> across the 2 data files. Is there a quick way to generate the third >> file >> which has the differenced values for each variables in the 2 >> original files? >> Thanks. >> >> Cheers, >> Wanli > > > > >__________________________________ >Yahoo! FareChase: Search multiple travel sites in one click. >http://farechase.yahoo.com >* >* 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/ -- =================================================== Eric G. Wruck Econalytics 2535 Sherwood Road Columbus, OH 43209 ph: 614.231.5034 cell: 614.330.8846 eFax: 614.573.6639 eMail: ewruck@econalytics.com website: http://www.econalytics.com ==================================================== * * 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/

**References**:**st: Re: new variable from 2 datasets***From:*Friedrich Huebler <huebler@rocketmail.com>

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