Agreed. What I was thinking, but didn't say explicitly was that one would need a large range of values; and that to get rid of the decimals, one could then multiply by some large multiple of 10 before truncating or rounding. Something like this, for example:

new file. dataset close all.

* Generate a file with lots of cases.

INPUT PROGRAM. LOOP case=1 TO 10000. END CASE. END LOOP. END FILE. END INPUT PROGRAM. EXECUTE.

* Compute a random ID number with a large range, and truncate. compute id = trunc(rv.uniform(1, 10**10)). exe.

* Use the NU function in AGGREGATE to obtain the * number of cases for each unique ID number.

AGGREGATE /OUTFILE=* MODE=ADDVARIABLES /BREAK=id /n_ID=Nu.

freq n_ID.

* If there are no duplicate IDs, the frequency * table should show only a value of 1 with the * frequency count being the number of cases in * the file.

I've run this a few times, and have not yet to see any duplicate IDs.

Cheers, Bruce

Rick Oliver wrote: > > Using this method, the unique IDs will contain decimals. If you truncate > or round the values, they may no longer be unique, unless the specified > range of values is considerably larger than the number of cases. > > > > From: > Bruce Weaver <bruce.weaver@hotmail.com> > To: > SPSSX-L@LISTSERV.UGA.EDU > Date: > 09/27/2010 02:34 PM > Subject: > Re: generating random (not consecutive) identification numbers > Sent by: > "SPSSX(r) Discussion" <SPSSX-L@LISTSERV.UGA.EDU> > > > > Debbie Hahs-Vaughn wrote: >> >> I have used COMPUTE ID=$CASENUM to generate consecutive identification >> numbers. However how can I generate identification numbers that are not >> consecutive but just purely random? I am trying to avoid having numbers >> that are only one digit difference in the ID so that there is less room >> for >> error in what we are trying to do. Thanks! >> >> > > Instead of $casenum, use one of the random variable functions, such as > RV.UNIFORM. From the Help: > > RV.UNIFORM. RV.UNIFORM(min, max). Numeric. Returns a random value from a > uniform distribution with specified minimum and maximum. See also the > UNIFORM function. > > If you want to obtain the same IDs every time you run the syntax, set the > value of the seed first (via the SET command). Here's the description of > the seed from the Help: > > "Initialization value for MC random number generator. The value must be a > positive integer that is less than 2,000,000,000 or the keyword RANDOM, > which randomly sets the initialization value. The default is 2,000,000." > > And finally, assuming you have one row per ID, you'll want to follow up > with a check for duplicate IDs. It's not very likely, but could happen. > > > > ----- > -- > Bruce Weaver > bweaver@lakeheadu.ca > http://sites.google.com/a/lakeheadu.ca/bweaver/ > > "When all else fails, RTFM." > > NOTE: My Hotmail account is not monitored regularly. > To send me an e-mail, please use the address shown above. > > -- > View this message in context: > http://spssx-discussion.1045642.n5.nabble.com/generating-random-not-consecutive-identification-numbers-tp2855693p2855817.html > > Sent from the SPSSX Discussion mailing list archive at Nabble.com. > > ===================== > To manage your subscription to SPSSX-L, send a message to > LISTSERV@LISTSERV.UGA.EDU (not to SPSSX-L), with no body text except the > command. To leave the list, send the command > SIGNOFF SPSSX-L > For a list of commands to manage subscriptions, send the command > INFO REFCARD > > > >

----- -- Bruce Weaver bweaver@lakeheadu.ca http://sites.google.com/a/lakeheadu.ca/bweaver/

"When all else fails, RTFM."

NOTE: My Hotmail account is not monitored regularly. To send me an e-mail, please use the address shown above.

-- View this message in context: http://spssx-discussion.1045642.n5.nabble.com/generating-random-not-consecutive-identification-numbers-tp2855693p2855887.html Sent from the SPSSX Discussion mailing list archive at Nabble.com.

===================== To manage your subscription to SPSSX-L, send a message to LISTSERV@LISTSERV.UGA.EDU (not to SPSSX-L), with no body text except the command. To leave the list, send the command SIGNOFF SPSSX-L For a list of commands to manage subscriptions, send the command INFO REFCARD