formula to gather non-empty cell info?
 

Hi,
I have 20 rows of cells which some have text info and some empty.
I need a formula to use to add-up these text info separeted with commas
excluding the blank cells.
Say A1 contains "this", E1 contains "is", and I1 contains "it!". All the
remaining cells till AA1 are blank (but can contain info).
I need to use a formula in cell AA1 that will gather non empty cells info in
row1 and display "this, is, it".
The same story applies for row2, row3, ...etc.
What should be the formula in AA1:AA20
Thanks
J_J