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st: Re: help creating a unique identifier


From   "Michael Blasnik" <michael.blasnik@verizon.net>
To   <statalist@hsphsun2.harvard.edu>
Subject   st: Re: help creating a unique identifier
Date   Thu, 17 Mar 2005 12:19:13 -0500

A similar question was recently asked and FAQ certainly addresses the unique identifier, but here are some answers:

egen SeqId=group(id_dom)

or

sort id_dom age
gen SeqId=sum(id_dom!=id_dom[_n-1])

for your second question, if there are no missing values on age, then this works:

bysort id_dom (age): gen byte hasover15=age[_N]>=15

otherwise, the easiest approach may be:

egen maxage=max(age),by(id_dom)
gen byte hasover15=maxage>15 if maxage<.


There is no need for collapse or merge and I can't see any reason why you would think so.

Michael Blasnik
michael.blasnik@verizon.net

----- Original Message ----- From: "Joao Pedro Wagner de Azevedo" <jazevedo@provide.com.br>
To: <statalist@hsphsun2.harvard.edu>
Sent: Thursday, March 17, 2005 11:42 AM
Subject: st: help creating a unique identifier



Hello,

I have a dataset with the variable id_dom (numeric) which s a unique
identifier of households and the variable age (see extract below). I would
like to create a couple of new variable and I would sincerely appreciate if
anyone on the list give me a hand.

First, I would like to create a sequential unique identifier such as
variable SeqID. Second, I would like to create a variable which would flag
all those households with at least on adult (age>=15).

Initially I would like to avoid having to use collapse and merge (given the
size of my dataset), and I have been trying to use command such as bysort,
_n and _N.

Any help will be much appreciated.

Cheers,

JP


id_dom age SeqID
9211001200001 5 1
9211001200001 10 1
9211001200001 15 1
9211001200001 20 1
9211001200001 25 1
9211001200002 5 2
9211001200002 10 2
9211001200002 15 2
9211001200002 20 2
9211001200002 25 2
9211001200003 4 3
9211001200003 8 3
9211001200003 12 3
9211001200003 16 3
9211002100002 3 4
9211002100002 6 4
9211002100002 9 4
9211002500004 7 5
9211002500004 14 5
9211002500004 21 5
9211002500004 28 5
9211002500004 35 5
9211002500004 42 5
9211002500004 49 5
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