topic Re: Why Variable value retaining??? in SAS Programming

Why Variable value retaining???

kuridisanjeev — Thu, 02 May 2013 12:27:58 GMT

Hello All..

As i was going through in data step processing and testing some sample SAS programs to check the way of datastep processing.

As i read in the SAS documentation ..

" the variable values in the program data vector are re-set to missing.".

But I am bit confused after looking the olg for bellow program ,the variable count value was retaining ,since i am not using RETAIN statement for that variable.

here i am posting my code and log as well..

CODE:

Data test;

Put _all_;

Input ID fee Name $;

Count+1;

Put _all_;

Cards;

100 1500 Sanju

100 2000 kuridi

100 3000 kumar

102 4000 sri

102 5200 nath

103 9512 sree

;

run;

LOG:

ID=100 fee=1500 Name=Sanju count=1 _ERROR_=0 _N_=1

ID=. fee=. Name= count=1 _ERROR_=0 _N_=2

ID=100 fee=2000 Name=kuridi count=2 _ERROR_=0 _N_=2

ID=. fee=. Name= count=2 _ERROR_=0 _N_=3

ID=100 fee=3000 Name=kumar count=3 _ERROR_=0 _N_=3

ID=. fee=. Name= count=3 _ERROR_=0 _N_=4

ID=102 fee=4000 Name=sri count=4 _ERROR_=0 _N_=4

ID=. fee=. Name= count=4 _ERROR_=0 _N_=5

ID=102 fee=5200 Name=nath count=5 _ERROR_=0 _N_=5

ID=. fee=. Name= count=5 _ERROR_=0 _N_=6

ID=103 fee=9512 Name=sree count=6 _ERROR_=0 _N_=6

ID=. fee=. Name= count=6 _ERROR_=0 _N_=7

Could any one explain me why Count variable still have some value when all other variables having missing values in the log.

Seeking for experts explanation..

Thanks&Regards.

Sanjeev.K

Re: Why Variable value retaining???

data_null__ — Thu, 02 May 2013 12:30:31 GMT

Did you happen to look a the documentation for the sum statement?

Re: Why Variable value retaining???

Ksharp — Thu, 02 May 2013 12:40:46 GMT

count + 1 ;

<=>

retain count 0;

count=count+1;

Re: Why Variable value retaining???

kuridisanjeev — Thu, 02 May 2013 13:20:22 GMT

Thank you,Got it.

In my above code i am trying to generate cumulative count variable per BY group(ID in my above code).it can be possible in the next datastep by using first. and last. automatic variables.

but Is it possible to get this in the same datastep??

Regards.

Sanjeev.K

Re: Why Variable value retaining???

Haikuo — Thu, 02 May 2013 13:33:56 GMT

change "count+1;" to "Count+1+(-count*(id ne lag(id)));"

Haikuo

Re: Why Variable value retaining???

Ksharp — Thu, 02 May 2013 13:59:14 GMT

and one more way:

if first.id then count=0;

count+1;

Re: Why Variable value retaining???

kuridisanjeev — Thu, 02 May 2013 14:02:40 GMT

Yes ..you are right..

but it can not be possible in the same datastep,i guess.

Re: Why Variable value retaining???

Ksharp — Thu, 02 May 2013 14:12:40 GMT

Then change:

if id ne lag(id) then count=0;

count+1;

Re: Why Variable value retaining???

kuridisanjeev — Thu, 02 May 2013 14:41:33 GMT

You make it So simple..

Have to learn a lot from you Mr...

Thank you all ...

Regards.

Sanjeev.K