Problem with my macro

[yahoo0806]

Hi all,

I recently wrote a SAS code as below.

The idea is if the &probf is => 0.1 then run the first model; if the &probf <0.1 then run the second model. This code runs fine however, when my &probf = 1.4513221E-6, it seems only run the first model regardless this probf value is actually less than 0.1.

Can you please let me know if you know why?

%if &probf >= 0.1 %then
%do;
ods output diffs=lsdiff LSMeans=lsm Tests3=Tests3;

proc mixed data=admmtt method=REML covtest alpha=0.05;
class usubjid trt01pn atptn siteid;
model aval= trt01pn atptn siteid trt01pn*atptn/htype=3 ddfm=KENWARDROGER;
repeated atptn/sub=usubjid type=&type1;
lsmeans atptn*trt01pn/pdiff cl alpha=0.05;
run;

%end;
%else %if 0 =< &probf < 0.1 %then
%do;
ods output diffs=lsdiff LSMeans=lsm Tests3=Tests3;

proc mixed data=admmtt method=REML covtest alpha=0.05;
class usubjid trt01pn atptn siteid;
model aval= trt01pn atptn siteid trt01pn*atptn trt01pn*siteid/htype=3 ddfm=KENWARDROGER;
repeated atptn/sub=usubjid type=&type1;
lsmeans atptn*trt01pn/pdiff cl alpha=0.05;
run;

%end;

[Astounding · Accepted solution]

The fact that the top half runs fine is a lucky accident.  Macro language is treating &PROBF as a character string and comparing it to the character string "0.1".  To make a numeric comparison, use:

%if %sysevalf(&probf >= 0.1) %then %do;

For the bottom half, macro language does not process multiple comparisons the same way that a DATA step would.  You will need to spell them out as two comparisons:

%else %if %sysevalf(0 <= &probf) and %sysevalf(&probf < 0.1) %then %do;

Technically, since you are using %else, you could eliminate the second comparison:

%else %if %sysevalf(0 <= &probf) %then %do;

[yahoo0806]

It worked! Many thanks! There are still a lot of things I need to explore and learn for SAS macro 🙂