Subsetting sas data set without creating new data file, rather creating a new variable <p>I have 3 variables in my data set: <code>id</code>, <code>Time</code>, and <code>y1</code>. </p> <p>Now I want to create a new variable with the value of <code>y1</code> when <code>Time=1</code>.</p> <p>How can I do it?</p>