Convert a character variable into a numeric variable

[Amy_W]

Hello,

I created two macro variables using proc sql select into. My expectation is that I will get two numbers and then continue to next step. The part of my is below:

proc sql noprint;
  select min(mean),max(mean) 
  INTO :mini,
  :maxes
  from plot1;
quit;

%LET low=%eval(&mini-10);
%LET upper=%eval(&maxes+10);

The error messages are:

ERROR: A character operand was found in the %EVAL function or %IF condition where a numeric
       operand is required. The condition was: 290.6-10
ERROR: The macro PLOT will stop executing.

I know one way to use input function in data step but not sure how to achieve my goal in this situation.

Any suggestions are welcome and thanks for all.

[Haikuo · Accepted solution]

%eval is only good for integers. replace it with %sysevalf().

[Amy_W]

Yes, that's it!

Thank you!

[ballardw]

How about

select (min(mean) -10),(max(mean)+10) into : low , :upper

and avoid the extra step?

Of course if you also need mini and maxes that's not needed.

[Amy_W]

That's really a good idea. Though I still need the %sysevalf function to convert it into numeric.

[data_null__]

Why put the numbers into macro variables at all?  What is your "next step"?

[Amy_W]

I need to plot thousands of pics. Those two numbers are the upper and lower bound of axes.

[data_null__]

For axis scaling I would look at the IML routine GSCALE.  I it takes min and max values and produces nice tick marks using some criteria that you can adjust, like Number of Ticks.