title: Concatenating cells in Excel ignoring blank cells
body: <p>I've searched through the site but can't seem to see anything that fits my problem.</p>
  
  <p>I have 7 columns</p>
  
  <p>User ID
  Session1
  session2
  session3
  session4
  session5
  session6</p>
  
  <p>Within the sessions 1-6, there will be a P or A to represent whether the user was "present" or "Absent". 
  Based on this master data, I have created a further 6 columns to the right of this will the same headings and input IF statements to say =IF(B2="P","",B$1) so that it will show the Session ID if the user was absent from that session.</p>
  
  <p>I then need to have all the users absent sessions within one column and that needs to be sepearated by commas.
  What I can't work out is how to get this without have duplicate commas where the cells are blank.</p>
  
  <p>Any ideas?</p>
  
  <p>Thanks
  James</p>