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Re: st: How to create a random number identifier number


From   Michael McCulloch <mcculloch@pinestreetfoundation.org>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: How to create a random number identifier number
Date   Wed, 11 Nov 2009 19:16:06 -0800

Anna,
This simulated example is a better approach, that is faithful to your need for the newpersonid to have 5 digits.
Michael

********* begin example
clear
set obs 11000
gen personid=_n
replace personid=personid+10000 if personid<10000
gen sortvar=1 + int(11000*uniform())

replace sortvar=sortvar+10000 if sort<10000
sort sortvar

gen newpersonid str5=_n
destring newpersonid, replace
replace newpersonid=newpersonid+50000 if newpersonid<11000

list personid newpersonid in 10050/11000
codebook
********* end example




Dear Anna, if you sort on some variable other than personid, or perform a random sort, you could then:
	gen new_personid = _n
This creates a variable which has a value equal to the sequence # of that record, which is why you have to create some sort order other than personid.
Michael



On Nov 11, 2009, at 6:37 PM, Anna Reimondos wrote:

Hello,
I am experiencing problems creating a unique set of number for my dataset.

I have a dataset with around 11,000 subjects or persons, and each one
of these subjects has a unique identifier that is 5 digits long
(personid).
I need to create a concordance file which list the original 5 digit
"personid" and matches this to another new randomly created identifier
for each person. This new identifier (new_personid) also has to be 5
digits long.

Example:
personid   new_personid
10526        35624
18594        21893
54632        12489

I have tried playing around with the gen  x = uniform() function but
to no avail. I am unable to create exactly 11,000 unique numbers with
5 digits.
I also tried just using the egen x=se() command, but then the ids are
sequential and not random and I am afraid then perhaps someone could
figure out how to match the personid and the newperson id....


Any help would be much appreciated,

Thanks
Anna

(Using STATA 10.1, Windows Vista)

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Michael McCulloch
Pine Street Foundation
124 Pine Street
San Anselmo, CA 94960-2674
tel:	415-407-1357
fax: 	206-338-2391
mm@pinestreetfoundation.org







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