SAS returning blank values - cant figure out why

[Jeg123]

I am trying to replace values using a script and for the first part I dont expect any changes, but SAS changes the values 'NaN' to '', which I dont understand why. Short example below

data test;
infile datalines delimiter=',';
	input var $ row date $ group $;
	datalines;
NaN,1,31OCT2016,-1-1d
NaN,2,31OCT2016,-1-1d
GCXK,3,30APR2017,-1-1d
;

DATA test2;
	SET test;
	BY group;
	RETAIN new_var;
	
	IF var NE 'NaN' then new_var = var;
	IF var EQ 'NaN' then var = new_var;

	IF last.var then new_var = 'NaN';

	DROP new_var;
RUN;

[Kurt_Bremser]

---

@Jeg123 wrote:

I am trying to replace values using a script and for the first part I dont expect any changes, but SAS changes the values 'NaN' to '', which I dont understand why. Short example below

data test;
infile datalines delimiter=',';
	input var $ row date $ group $;
	datalines;
NaN,1,31OCT2016,-1-1d
NaN,2,31OCT2016,-1-1d
GCXK,3,30APR2017,-1-1d
;

DATA test2;
	SET test;
	BY group;
	RETAIN new_var;
	
	IF var NE 'NaN' then new_var = var;
	IF var EQ 'NaN' then var = new_var;

	IF last.var then new_var = 'NaN';

	DROP new_var;
RUN;

---

Your code contains a mistake.

Maxim 2: read the log:

36         DATA test2;
37         	SET test;
38         	BY group;
39         	RETAIN new_var;
40         	
41         	IF var NE 'NaN' then new_var = var;
42         	IF var EQ 'NaN' then var = new_var;
43         
44         	IF last.var then new_var = 'NaN';
45         
46         	DROP new_var;
47         RUN;

NOTE: Variable 'last.var'n is uninitialized.
NOTE: There were 3 observations read from the data set WORK.TEST.
NOTE: The data set WORK.TEST2 has 3 observations and 4 variables.
NOTE: DATA statement used (Total process time):
      real time           0.01 seconds
      cpu time            0.00 seconds

Just to get you on the right path: ask yourself: "from where does the first NOTE come from?"

About your question:

In obs #1, the first condition is FALSE, so new_var is not set.

The second condition is TRUE, so var is set to new_var (which is still missing, see above)

In obs #2, the same happens.

In obs #3, the first condition is TRUE, so new_var is set.

The second condition is FALSE, so var is not changed.