Date:         Sun, 3 Aug 2008 09:02:58 -0700
Reply-To:     Learner <cnfengshuang@GMAIL.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Learner <cnfengshuang@GMAIL.COM>
Organization: http://groups.google.com
Subject:      conditonally add/remove variables and numerical programming
Comments: To: sas-l@uga.edu
Content-Type: text/plain; charset=ISO-8859-1

Hi,

I have a large set of time series data to process, variables include
month, flow, and other values.

For each month, if flow>0, then I will generate a variable a_month,
where month refers to the particular month. I know how to generate
this "a_month" variable now. (Thanks to the help I got here!)    There
will be a group of such variables for each year. For my computation, I
need delete all these "a_month" at the end of each year, and I will
repeat the same thing for the next year.   I need to drop all the
a_month variables to save the system resource.

For each month, with the variables created above, I need to do a
numerical "Goal seek" programming.  Without, creating/deleting the
variables correctly, now I couldn't do this.

Basically, what I want to do is as below:

if Flow>0
=> create a new variable "a_month" for this month
=> use all the up-to-current "a_month" variables to do numerical "Goal
Seek"
=>...(Do this for each month during a year)
=> at year end, delete all the previous "a_month" variables
=>create a new "a_month" variable in the first month of the following
year
=>repeat the above routine for each year.

What I know now, is to create global "a_month" variables. But I hope
to execute the program month by month, instead of having a "a_month"
variable for all the month. Could anyone help me? Thanks a lot!!

Learner