Put all the possible characters in a cell, and name it as "list".
Then
=MID(list,1+INT(RAND()*LEN(list)),1)
will give a random character from the list. Use as many of these
as you need.
Is the word 'list' in the formular the name of the header for the list? The
formular is not working. It's returning a #NAME? error. FYI, I am using
Excel 2003.
(1) How can I make sure that the characters generated are not repeated in
any of the cells?
(2) Some cells returns null characters while some others return characters
whose length is less than the specified length in LEN. How can I control the
length of characters the code will return?