# Re: st: Observation variable transformation

 From Philip Ryan To statalist@hsphsun2.harvard.edu Subject Re: st: Observation variable transformation Date Sun, 11 Sep 2005 09:23:54 +0930

```Given X has contiguous increasing integer values from 1 to _N, the -egen-
function -seq()- will also accomplish this.

egen X1 = seq(), block(10)

see -help egen-

[I do not think you mean "successive observations of 10 *variables*. I think
you mean "successive observations (on a single variable) in blocks in 10".
Correct me if I'm wrong, but confusion over variable/observation terminology
can ambush both the poser of and the responder to a question.]

Phil

Quoting Svend Juul <SJ@SOCI.AU.DK>:

> Kelly wrote:
>
> I have created an observation variable X (e.g. gen X=_n) for a large data
> set. How can I create a new variable that is unique for successive
> observations of 10 variables (i.e. i want this variable to be equal to 1 in
> obs 1-10, 2 in 11-20, and so forth)?
> ----
>
> Try this:
>     clear
>     set obs 50
>     gen X=_n
>     gen X1 = int((X+9.5)/10)
>     list
>
> I added 9.5, not 9, to prevent rounding errors.
>
> Hope this helps.
>
> Svend
>
>
>
> ________________________________________________________
>
> Svend Juul
> Institut for Folkesundhed, Afdeling for Epidemiologi
> (Institute of Public Health, Department of Epidemiology)
> Vennelyst Boulevard 6
> DK-8000 Aarhus C,  Denmark
> Phone, work:  +45 8942 6090
> Phone, home:  +45 8693 7796
> Fax:          +45 8613 1580
> E-mail:       sj@soci.au.dk
> _________________________________________________________
>
> *
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>

--
Philip Ryan
Associate Professor
Department of Public Health

Associate Dean (IT)
Faculty of Health Sciences

Head, Data Management and Analysis Centre
Department of Public Health and Department of General Practice

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