title: CONCATENATE array
body: <p>I'd like to CONCATENATE some columns and between them there has to be this. ";\"
  The problem is that different rows have different numbers of columns. So for  example:</p>
  
  <pre><code>      A             B             C
  
  1  Image1.jpg     Image2.jpg    Image3.jpg
  2  Image1.jpg     Image2.jpg
  3  Image1.jpg  
  </code></pre>
  
  <p>If I CONCATENATE the three columns the third will look like this <code>Image1.jpg;\;\</code></p>
  
  <p>Is there an option to CONCATENATE the columns only if it's not empty?</p>