# st: AW: Splitting panel in 3 groups: gen byte

 From "Martin Weiss" To Subject st: AW: Splitting panel in 3 groups: gen byte Date Wed, 17 Jun 2009 09:54:16 +0200

```<>

That was a little trick to get a random order into your panel. You want to
take a look at Nick`s
http://www.stata-journal.com/sjpdf.html?articlenum=pr0016
and
http://www.stata-journal.com/sjpdf.html?articlenum=pr0004
to get a grip on this thing.

As the first article shows, you can extend the -cond()- to several nested
conditions. For three groups and w/o the "i", which complicates things at
first:

********
clear*
set obs 10000

gen random=runiform()
sort random
gen byte group=cond(_n<=_N/3,1, ///
cond(_n>_N/3&_n<=_N*2/3,2, ///
3))
ta group
********

HTH
Martin

-----Ursprüngliche Nachricht-----
Von: owner-statalist@hsphsun2.harvard.edu
[mailto:owner-statalist@hsphsun2.harvard.edu] Im Auftrag von John Antonakis
Gesendet: Mittwoch, 17. Juni 2009 09:47
An: statalist@hsphsun2.harvard.edu
Betreff: st: Splitting panel in 3 groups: gen byte

Hi:

Martin recently helped with me with some code, to randomly split panel
data equally into two groups (which I then collapsed afterwards).

I am trying to understand the code regarding the split. My panel
identifier is "i".

gen random=runiform()
sort i random
by i: gen byte group=cond(_n<=_N/2,1,2)

So, how to I split into 3 groups or 4 groups?  I am not sure what the
"gen byte" command does and how the numbers 2,1,2 relate to the command.

John.

--
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