Counter Variable to Split File by Month

[jimjohn]

can someone plz help me with this:

two of the variables i have in my data set are ID and Age. So, for each ID, I have a different row of data for each month. but the age variables aren't always the same. ie one ID could go Age = 28, 58, 88, etc. another ID could go Age = 29, 59, 89,...etc. i want to be able to split the file by monthly age so I can run some statistical analyses per month. is there any way i can create a new counter variable that for each ID, goes in increasing order of age. and then the counter resets once i hit another ID. That way any value of 1 in my new variable would stand for data in the first month of an ID, any 2 would stand for data in the second month of an ID, etc.

any ideas? thanks!

[Richard Ristow]

At 04:42 PM 2/26/2009, jimjohn wrote:

two of the variables i have in my data set are ID and Age. For each ID,
I have a different row of data for each month. [...] Is there any way i can
create a new counter variable that for each ID, goes in increasing order of
age. and then the counter resets once i hit another ID.

Creating a counter variable within groups defined by an ID variable is something of a FAQ:

FAQ: Sequence numbers & random sequence numbers for cases

This is only relevant for sequencing within groups of cases. For sequencing the whole file,

COMPUTE SeqnNumb = $CASENUM.

is much the easiest.
........................
To create sequence numbers within groups (letters refer to the citations at the end of this posting):

Using a transformation program(a):

DO IF       $CASENUM EQ 1
        OR  Group NE LAG(Group).
.  COMPUTE SeqnNumb = 1.
ELSE.
.  COMPUTE SeqnNumb = LAG(SeqnNumb) + 1.
END IF.


Using CREATE(b):

COMPUTE NOBREAK = 1.
FORMATS NOBREAK (F2).

SPLIT FILE BY Group.
CREATE SeqnNumb = CSUM(NOBREAK).


Using RANK(c):

COMPUTE id=$casenum.
RANK VARIABLES=ID(A) BY Group
   /RANK INTO SeqnNumb
   /PRINT=NO .
DELETE VARIABLES id.
FORMAT SeqnNumb (F4).


Random sequencing within groups(d):

COMPUTE RandKey   = RV.UNIFORM(0,1).

RANK RandKey (A)
  BY GROUP
   /RANK INTO RandSeqn.

....................................
(a) This method is around. I've written the code for this FAQ, rather than looking for a citation.

(b) Date: Tue, 13 Nov 2007 22:46:32 -0500
From:     Richard Ristow <[hidden email]>
Subject:  Re: Consecutive numbers of different size
To:       [hidden email]

(c)Date:  Wed, 14 Nov 2007 07:42:06 +0100
From:     Marta García-Granero <[hidden email]>
Subject:  Re: Consecutive numbers of different size
To:       [hidden email]


(d)Date:  Tue, 15 Jan 2008 11:15:44 -0800
From:     King Douglas <[hidden email]>
Subject:  Re: drawing samples for hundreds of workers
To:       [hidden email]

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