Formula To Return Zero If Cell Is Blank?

I have a column of imported data like this, with scattered blank cells:

Rd Frnt200634350464300399636350

I am doing a multiple regression where the above are independent variables. I usually have hundreds of variables in a column like this. Because each cell must have a value in it (the regression won't accept blanks), rather than manually fill the blank cells with a 0, I set up an adjacent column to convert the blanks to a 0 and regress off that column. But every formula I try still produces a blank in that adjacent column. I have tried things like: =IF(A1="",0,A1) but they do not work. I always get a blank in the adjacent column when the original cell is blank. Can't get a 0 in there.