Re: st: any idea?

["Y.R.E. Retamal" <yrer2@cam.ac.uk>]

Dear Red Owl and Nick

Thank you very much for your response. The code works perfectly, just as 
I need.
Best wishes

Rodrigo


On 2013-12-14 22:31, Nick Cox wrote:
> In addition to Red's helpful suggestions, note that technique for such
> paired data was discussed in
>
> http://www.stata-journal.com/sjpdf.html?articlenum=dm0043
>
> which is publicly accessible. The problem is that the identifiers in
> Rodrigo's example appear to make little sense. How is Stata expected
> to know that 1 and 4, 2 and 5, 3 and 6 are paired? Perhaps the
> structure of the dataset is clearer in practice. If so, basic
> calculations are just a couple of lines or so.
>
> Nick
> njcoxstata@gmail.com
>
>
> On 14 December 2013 15:33, Red Owl <rh.redowl@liu.edu> wrote:
> > Rodrigo,
> >
> > The following code demonstrates an approach with basic loops.
> > It could be made more efficient with a different loop
> > structure, but this approach may be more informative.
> >
> > *** BEGIN CODE ***
> > * Build demo data set.
> > clear
> > * Length is capitalized to distinguish from length().
> > input id str5(side) Length
> > 1 right 10
> > 2 right 15
> > 3 right 11
> > 4 left  13
> > 5 left  10
> > 6 left  12
> > end
> >
> > gen byte newvar1 = .
> > forval i = 1/3 {
> >   replace newvar1 = Length[`i'] - Length[4] in `i'
> >   }
> > forval i = 4/6 {
> >   replace newvar1 = Length[`i'] - Length[1] in `i'
> >   }
> >
> > gen byte newvar2 = .
> > forval i = 1/3 {
> >   replace newvar2 = Length[`i'] - Length[5] in `i'
> >   }
> > forval i = 4/6 {
> >   replace newvar2 = Length[`i'] - Length[2] in `i'
> >   }
> >
> > gen byte newvar3 = .
> > forval i = 1/3 {
> >   replace newvar3 = Length[`i'] - Length[6] in `i'
> >   }
> > forval i = 4/6 {
> >   replace newvar3 = Length[`i'] - Length[3] in `i'
> >   }
> >
> > list, noobs sep(0)
> > *** END CODE ***
> >
> > Good luck.
> >
> > Red Owl
> > redowl@liu.edu
> >
> >
> > > Y.R.E. Retamal" <yrer2@cam.ac.uk> Sat, 14 Dec 2013 12:08:42:
> > >
> > > Dear list
> > >
> > > I am very complicated trying to perform an analysis using STATA and I
> > cannot find the way. Maybe you could help me. I want to create some 
> > new
> > variables containing the difference between the length of two
> > individuals from different groups:
> > > id     side     length      newvar1       newvar2      newvar3
> > > 1      right      x           x-j           x-k          x-l
> > > 2      right      y           y-j           y-k          y-l
> > > 3      right      z           z-j           z-k          z-l
> > > 4      left       j           j-x           j-y          j-z
> > > 5      left       k           k-x           k-y          k-z
> > > 6      left       l           l-x           l-y          l-z
> > >
> > >
> > > I do not know if I do explain myself clearly, the individuals are
> > bones (clavicles, for example), so it is possible that some right
> > clavicles pair-match with left clavicles, following the idea that an
> > individual has bone of similar length.
> > > Any help could bring me a light!
> > > Best wishes
> > >
> > > Rodrigo
> > *
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> > *   http://www.ats.ucla.edu/stat/stata/
> *
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