topic Need Help on PDV in SAS Programming

Need Help on PDV

Varun — Tue, 17 Apr 2012 05:19:19 GMT

I have this SAS sample code:

data BEFORE;

input v1 v2;

datalines;

1 2

;

data AFTER;

put 'Before IF: ' _ALL_;

if _N_ = 1 then set BEFORE;

put 'After IF : ' _ALL_;

run;

The output is:

BEFORE: v1=. v2=. _ERROR_=0 _N_=1

AFTER : v1=1 v2=2 _ERROR_=0 _N_=1

BEFORE: v1=1 v2=2 _ERROR_=0 _N_=2

AFTER : v1=1 v2=2 _ERROR_=0 _N_=2

And the output file contains:

Obs v1 v2

1 1 2

2 1 2

I would like to understand why two observations set in the new dataset with repeated values. Please clerify.

Hima — Tue, 17 Apr 2012 13:14:58 GMT

The reason why it's appearing twice is because of the below code

if _N_ = 1 then set BEFORE;

This step copies the results from before and pastes it After data set.

put 'After IF : ' _ALL_;

_ALL_ does the same but it copies the results from AFTER and pastes it again.

Fix to the code would be

data BEFORE;
input v1 v2;
datalines;
1 2
;

data AFTER;
put 'Before IF: ' _ALL_;
set BEFORE;
put 'After IF : ' _ALL_;
;
run;

proc print; run;

art297 — Tue, 17 Apr 2012 14:11:55 GMT