title: How do you specify a variable to be binary in SAS?
body: <p>Suppose we have the following:</p>
  
  <pre><code> proc optmodel;
       var  x{1..3} &lt;= 1 integer;
  </code></pre>
  
  <p>I want the variables to be 0 and 1 only. How do I specify this in the above statement?</p>