empty cells
 

in a spreadsheet, i have a series of dates in a column, but many are blank.
this column is created via formula: in a1: =if(c1="is a date",b1,""),
where info in column b are dates, but not all are wanted in column a's
formula.
the problem arises in code when i try to define what's in column a (dates
and blanks).
for i = 1 to 100
maturitydate=cells(i,1).value
next i

if cells(i,1) are blank (caused by "" in excel formual), code stops and
cannot assign a blank to 'maturitydate'. if, however, i go back and
overwrite the formula in excel and simply clearcontents, it works in code.
can i write a formula in excel spreadsheet that has false statement that
will be treated in code as blank? i can use "0" as false statement vs. "",
but it messes other things up. any thoughts? thanks, mike allen