Assignment Statements and Operators

An assignment statement creates or updates a variable: variable = expression;.

Arithmetic

data _null_;
   a = 17;
   b = 5;
   sum = a + b;
   diff = a - b;
   prod = a * b;
   quot = a / b;
   power = 2 ** 10;
   remainder = mod(a, b);
   put sum= diff= prod= quot= power= remainder=;
run;

sum=22 diff=12 prod=85 quot=3.4 power=1024 remainder=2

• ** is exponentiation.
• / always gives a full result — there's no integer division operator; use int(a / b) or floor(a / b).
• Parentheses control the order, as in math.

Comparisons and logic

A comparison evaluates to 1 (true) or 0 (false), which you can store or add up:

data flags;
   set sashelp.class;
   tall = (height > 65);
   teen = age in (13, 14, 15, 16, 17, 18, 19);
   keep name height age tall teen;
run;

proc print data=flags(obs=4);
run;

Obs    Name       Age    Height    tall    teen

  1    Alfred      14     69.0       1       1
  2    Alice       13     56.5       0       1
  3    Barbara     13     65.3       1       1
  4    Carol       14     62.8       0       1

(obs=4) is a data set option: it limits the procedure to the first four rows.

Joining text

|| concatenates, but keeps the trailing blanks that pad character variables. The CAT family trims for you — CATX also inserts a separator:

data _null_;
   length first last $ 10;
   first = 'Ada';
   last = 'Lovelace';
   joined = first || last;
   nice = catx(' ', first, last);
   put joined=;
   put nice=;
run;

joined=Ada       Lovelace
nice=Ada Lovelace

first is 10 characters long, so 'Ada' is stored as 'Ada' plus 7 blanks — and || keeps them.

Practice

Compute the body-mass index for the first three students in SASHELP.CLASS: bmi = 703 * weight / height**2 (weight in pounds, height in inches), rounded to one decimal with round(x, 0.1).

data bmi;
   set sashelp.class(obs=3);
   bmi = round(703 * weight / height**2, 0.1);
   keep name height weight bmi;
run;

proc print data=bmi;
run;

Obs    Name       Height    Weight     bmi

  1    Alfred      69.0      112.5    16.6
  2    Alice       56.5       84.0    18.5
  3    Barbara     65.3       98.0    16.2