title: Conditionally replace column values with column name in SAS dataset
body: <p>I have a SAS dataset as follow :</p>
  
  <pre><code>Key    A    B    C    D    E
  001    1    .    1    .    1
  002    .    1    .    1    .
  </code></pre>
  
  <p>Other than keeping the existing varaibales, I want to replace variable value with the variable name if variable A has value 1 then new variable should have value A else blank.</p>
  
  <p>Currently I am hardcoding the values, does anyone has a better solution?  </p>