Re: st: any idea?

[Red Owl <rh.redowl@liu.edu>]

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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