Checking if macro variable is numeric or not.

[WimB]

I'm trying to write where any given macro variable can be numeric or character as the list of possible input value could be any integer, possibly preceded or followed by a character (i.ee = -1, 0, 1, d1, w9e), but something is off. See below for the simplified code:

Checking if variable is integer:

%macro isnum (mv);
   %eval(not %sysfunc(verify(&mv,-0123456789)));
%mend isnum;

%macro DefineDate(dt1,dt2,dt3);														
	...				
	%do i = 1 %to 3;
		%put Test dt&i. = &&dt&i.;
		%if %length(&&dt&i.) ne 0 %then %do;
			%put Variable dt&i. = &&dt&i.;
			%if %isnum(&&dt&i.) = 1 %then %do;
				%put dt&i. isnum successful;
			%end;
			%else %do;
				%put dt&i. isnum did not run;
			%put dt&i. numericity is %isnum(&&dt&i.);
		%end;
		%else %put dt&i. does not exist;
	%end;	
%mend;
%DefineDate(dm1,0)

The output to the log is:

Test dt1 = dm1
Variable dt1 = dm1
dt1 isnum did not run
dt1 numericity is 0;
Test dt2 = 0
Variable dt2 = 0
dt2 isnum did not run
dt2 numericity is 1;
Test dt3 =
dt3 does not exist

I can't understand why I can't get the %IF conditional to run in the second step, despite it returning 1 in the identical put statement.

Thank you

[Reeza]

I think the NOT in the %eval is incorrect. Would the notdigit or INPUTN maybe be easier to use than verify? If you explain your latter usage of these values, there may be other options.

[novinosrin]

In my opinion @Reeza is bang on target with notdigit being the sweetest. However, You could use %sysevalf to evaluate to a Boolean result. I learned that from Guru of Gurus @data_null__ . Little too late and tired in Chicago night, but I hope I comprehended the topic. 

[WimB]

I tried notdigit, but it only works on character variables and then I'd get the error for numeric inputs that there is a NUM variable where notdigit expects a CHAR variable.

Also not sure about the "not" in the %eval being incorrect: if it was, why would it return a 1 in the put statement for the correct variable?

I'll struggle on for a bit trying to see another solution with notdigit and ssyevalf. Report back later.

[Reeza]

All macro variables are character to start so anydigit will work, make sure to not use quotes.

[WimB]

Ok, I'll retry and update in a bit. Thanks for your time, much appreciated!

[novinosrin]

a simple test-log report

2078 %put %sysfunc(notdigit(a123));
1

2081 %put %sysfunc(notdigit(123));
0

[Reeza]

Do you need to account for decimals and percentages or will it always be integers?

[novinosrin]

brilliant question and %sysevalf has the answer

log:
 %put %SYSEVALF( %sysfunc(notdigit(123.22)) , boolean );
1
I think my usage is wrong but we are close

[WimB]

The %isnum macro also returned 1, despite the %IF not returning true for checking = 1

%put dt&i. numericity is %isnum(&&dt&i.)

This returns dt2 numericity is 1, so I got that far too.

I also tried NOTDIGIT and I got this in the log:

ERROR: Required operator not found in expression: notdigit(&&dt&i.) = 0 
ERROR: The macro DEFINEDATE will stop executing.

I think I'll give up on these methods for now and try to use prxmatch for a bit. This is breaking my mind why it returns 1 in a %PUT, but can't evaluate %IF %ISNUM(&&dt&i.) = 1 as true at the same time with all other proposed solutions giving me errors.

[novinosrin]

I will test tomorrow morning and get to the bottom of it but I'm more than 100% certain , somebody else will give you the much needed solution while my night passes by sleeping. Hang in there

[WimB · Accepted solution]

I just been able to solve it!

%if %sysfunc(prxmatch('^-?\d+$',&&dt&i.)) = 1 %then %do;

This did the trick for me and should be easily changable should the requirements someday change to include decimals 🙂

[novinosrin]

very nice

[FreelanceReinh]

---

@WimB wrote:

This did the trick for me and should be easily changable should the requirements someday change to include decimals 🙂

---

For more general types of numeric values (including decimals and scientific notation) there's also the %DATATYP Autocall Macro.

[Tom]

The real  problem is that you included a semi-colon in your macro "function".  A macro that only generates part of a statement cannot generate a semi-colon because that will prematurely terminate any statement that you try to use it in.

1    %macro isnum (mv);
2       %eval(not %sysfunc(verify(%superq(mv),-0123456789)))
3    %mend isnum;
4
5    %put %isnum(fred);
0
6    %put %isnum(123);
1
7    %put %isnum(-1.2.3);
0
8    %put %isnum();
1