title: Getting data in variable if value is set
body: <p>I have 3 variable mat , follow , not 
  only one can have value at a time what I want if any of the variables has value it should be updated in msg</p>
  
  <p>this is my logic</p>
  
  <pre><code>&lt;?php     
      $mat = $this-&gt;input-&gt;post('mater_mesaage') ;
      $folow = $this-&gt;input-&gt;post('follow_message') ;
      $not = $this-&gt;input-&gt;post('not_inst_comment') ;     
      if (isset($mat)){
          echo "Mat";
          $msg = $mat  ;
      } 
      if (isset($folow )) {
          echo "folow" ;
         $msg = $folow ;
      }
      if (isset($not)){
          echo "not" ;
          $msg = $not ;
      }
      echo $msg ;
  ?&gt;
  </code></pre>