# st: AW: dealing with duplicate "pairs" of columns

 From "Martin Weiss" To Subject st: AW: dealing with duplicate "pairs" of columns Date Wed, 10 Feb 2010 15:35:58 +0100

```<>

*************
clear*

input byte(Person1_id ClosestPerson  Person1_age)
1			2			10
2			1			20
3			1			30
4			3			40
end

gen lower=min( Person1_id, ClosestPerson)
gen upper=max( Person1_id, ClosestPerson)
bys lower upper ( Person1_age): gen byte dup=!(_N==1)
by lower upper ( Person1_age): replace dup=2 if _n==_N &dup!=0
l, noo
*************

HTH
Martin

-----Ursprüngliche Nachricht-----
Von: owner-statalist@hsphsun2.harvard.edu
[mailto:owner-statalist@hsphsun2.harvard.edu] Im Auftrag von Vitorino, Maria
Ana
Gesendet: Mittwoch, 10. Februar 2010 15:21
An: statalist@hsphsun2.harvard.edu
Betreff: st: dealing with duplicate "pairs" of columns

Hi all,
I was wondering if there was a relatively simple way to achieve the
following:

My data looks like this:

Person1_id ClosestPerson  Person1_age
1			2			10
2			1			20
3			1			30
4			3			40
...

What I would like to do is to signal "duplicate" rows for which Person1 is
the oldest. Since this is hard to explain, the resulting data would be for
the example above:

Person1_id ClosestPerson  Person1_age  dup
1			2			10
1
2			1			20
2
3			1			30
0
4			3			40
0
...

Note that the column dup has the following coding:
dup=1 if there is another pair of ppl identical to the one in this row and
Person1 is the youngest of the pair
dup=2 if there is another pair of ppl identical to the one in this row and
Person1 is the oldest of the pair
dup=0 if there is no other pair of ppl identical to the one in this row

Hope this isn't too confusing...
Suggestions are welcome!

Thanks,
Maria Ana

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```