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Date:         Tue, 23 Oct 2007 14:16:03 -0400
Reply-To:     Sigurd Hermansen <HERMANS1@WESTAT.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Sigurd Hermansen <HERMANS1@WESTAT.COM>
Subject:      Re: Newbie wants to program
Comments: To: Pat <PLarkin2@gmail.com>
In-Reply-To:  <1193160593.588443.224810@q5g2000prf.googlegroups.com>
Content-Type: text/plain; charset="us-ascii"

Pat: F**TRAN isn't actually an assembler language, just an early procedural language. With some effort you can write SAS programs that look much like F**TRAN. Sounds as if you are heading in that direction.

You have selected a 'look ahead in a file' problem and an array solution. SAS offers array solutions as well, but also offers a couple less procedural (more declarative) alternatives:

- sort the dataset in descending order and use the LAG3() function to look back three rows. The first three rows (in descending order) will then have missing or NULL values and can be deleted; - assign sequential row numbers to the rows of data and use SAS SQL to join the dataset to itself (reflexive join) on n=n+3.

Even better, use SAS procedures appropriate for analysis of time series or repeating measures or groups (or whatever you are analyzing). For that you will need to add identifying information to your data array.

If you really prefer to stay in the world of numeric arrays and you have PROC IML licensed, the matrix operations in IML may give you what you want. Much depends on what you might want to do next. S

-----Original Message----- From: owner-sas-l@listserv.uga.edu [mailto:owner-sas-l@listserv.uga.edu] On Behalf Of Pat Sent: Tuesday, October 23, 2007 1:30 PM To: sas-l@uga.edu Subject: Newbie wants to program

I work with financial data at a university using SAS 9.1. In the past, I've manipulated my data using an assembly language program that I'm too embarrassed to name (but it starts with an F and ends with a tran) and then entered it into SAS to do regressions and other statistical procs. I've heard that this is a waste of time and that I can just do all of the manipulations in SAS. I am having trouble figuring out how to do that. I know that SAS has an array statement, but I don't think that I really want to make an entire row into an array. Let me try to explain what I'd like to do. It's pretty simple:

x1 y1 z1 x2 y2 z2 . . . . . . xn yn zn

I would like to be able to create a variable, call it w, and make it an array with dimensions n-3 rows by 1 column. Then, do something like this, but using SAS code:

do i=1,n-3 if x(i+3) not equal to -99 then w(i) = x(i+3) + y(i+3) / z(i+3) else w(i) = -99 end if end do

Thanks for your attention


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