topic Comparison between two values are Giving wrong results in %If in SAS Procedures

Comparison between two values are Giving wrong results in %If

Saugata — Wed, 23 Apr 2014 07:06:44 GMT

Hi All,

I am writing the below %If else statement:

%if (%sysfunc(abs(%sysevalf((47496-49030.8)/49030.8)*100)) gt 12)then %do;

%Put I am in the Loop;

%End;

In log it is showing that:

MLOGIC(S1): %IF condition
(%sysfunc(abs(%sysevalf((47496-49030.8)/49030.8)*100)) gt 12)
is TRUE

Whereas if I check the value of the calculation in the below chunk:

%let a= %sysfunc(abs(%sysevalf((47496-49030.8)/49030.8)*100));

%Put &a.;

Then in the Log it is showing:

SYMBOLGEN: Macro variable A resolves
to 3.130277295087
3.130277295087

So, now my question is how can 3.130277295087 be greater than 12?

I believe this has to do something with how SAS stores the data internally in hexadecimal form. But I am not very sure.

Can anybody shed some light on this one?

Note: If I put a round function in the %If statement, then the result comes out as expected (i.e.False).

Thanks all in advance for your help.

Regards,

Saugata Mukherjee.

Re: Comparison between two values are Giving wrong results in %If

Kurt_Bremser — Wed, 23 Apr 2014 08:36:44 GMT

Without the round function, you have a period in the number, which causes the macro processor to treat the numbers as character strings and do a string comparison, which yields the undesired result.

See the documentation of the %sysevalf function, which will help here.

Re: Comparison between two values are Giving wrong results in %If

Saugata — Wed, 23 Apr 2014 09:57:50 GMT

Hi Kurt,

So, does that mean that it is not possible to do floating point comparison in %If statement?

Regards,

Saugata Mukherjee.

Re: Comparison between two values are Giving wrong results in %If

Kurt_Bremser — Wed, 23 Apr 2014 10:24:31 GMT

Have a look at this:

SAS(R) 9.2 Macro Language: Reference

Right in the middle you have an example of how the %sysevalf function makes it possible.

Re: Comparison between two values are Giving wrong results in %If

SKK — Wed, 23 Apr 2014 11:09:55 GMT

Try this:

%if %sysevalf((%sysfunc(abs(%sysevalf((47496-49030.8)/49030.8)*100))) gt 12) %then %do;

%Put I am in the Loop;
%End;

Re: Comparison between two values are Giving wrong results in %If

Saugata — Wed, 23 Apr 2014 11:58:42 GMT

Thanks a lot Kurt. Now I have a better understanding of this :smileylaugh:

Re: Comparison between two values are Giving wrong results in %If

Saugata — Wed, 23 Apr 2014 11:59:30 GMT

Thank you