SAS Macro functions – %eval() and %sysevalf()

The %EVAL function evaluates integer arithmetic or logical expressions. %EVAL operates by converting its argument from a character value to a numeric or logical expression. Then, it performs the evaluation. Finally, %EVAL converts the result back to a character value and returns that value.

Operands that contain a period character cause an error when they are part of an integer arithmetic expression. The following examples show correct and incorrect usage, respectively:

%let d=%eval(10+20);     /* Correct usage */

%let d=%eval(10.0+20.0); /* Incorrect usage */

When %EVAL encounters a value containing a period, it displays an error message about finding a character operand where a numeric operand is required.

view source

print?

%let a=1+2;

%let b=10*3;

%let c=5/3;

%let eval_a=%eval(&a);

%let eval_b=%eval(&b);

%let eval_c=%eval(&c);

%put &a is &eval_a;

%put &b is &eval_b;

%put &c is &eval_c; The %SYSEVALF function evaluates arithmetic and logical expressions using floating-point arithmetic and returns a value that is formatted using the BEST32. format. The result of the evaluation is always text. % SYSEVALF is the only macro function that can evaluate logical expressions that contain floating point or missing values. Specifying a conversion type can prevent problems when %SYSEVALF returns missing or floating point values to macro expressions or macro variables that are used in other macro expressions that require an integer value. Syntax: %SYSEVALF(expression<, conversion-type>) Taking an example… view source print? %let a=100; %let b=101.590; %let x=%sysevalf(&a+&b); %let y=%sysevalf(&a +&b, boolean); %let z=%sysevalf(&a +&b, ceil); %let v=%sysevalf(&a +&b, floor); %let w=%sysevalf(&a +&b, int); %put The result with SYSEVALF is: &x; %put  The BOOLEAN value is: &y; %put  The CEIL value is: &z; %put  The FLOOR value is: &v; %put  The INTEGER value is: &w; http://technico.qnownow.com/sas-macro-functions-eval-and-sysevalf-2/

parmbuff (or Pbuff) in SAS macro

%macro demo(a=1, b=2)/parmbuff;
%put buffer holds |&syspbuff|;
%put &=a;
%put &=b;
%mend demo;
%demo(a=aa)

%demo(a=silly, d=unknown)