Normally I would give this problem more attention and not ask
for the solution so quickly however I have too many other things to consider at the moment.
I have never actually use Excel formula programming, since the last time I actually worked with Excel was for book keeping in some econ class in 8th grade.

I realize it can quite powerful and I am trying to determine what is the best method given
how many ways I could approach this problem. First I have several large sets of data (combined 2.6 million rows) so we had to split those because Excel won't handle it apparently.

The main issue is that while our is all discrete we wish to have them all numeric (there are some categorical variables which are ID, etc). The idea is to create a new column, then have an indicator function to give a number for each class. There are some of these variables which have only several classes and so nested if statements, and while it is my understanding that it supports up to 64 nested if, this seems rather barbaric.

I do have separate sheets for the list of classes and I was considering trying to pair this
with vlookup, but I ran into a tip that I think could be modified to make it simpler.

At http://spreadsheetpage.com/index.php/tip/C17/P20/
there is a formula , =IF(B1<>"",COUNTA($B$1:B1)&".","") for indexing a column. I read about using COUNTIF to reference previously identified classes (in rows above). I am not sure how I would do this. I imagine there is a simpler way, which would be great.

In addition is there a function/macro for loading either partially or only certain column so that deal with each one alone. At the moment I am stuck with a netbook and even while split into pieces they are approximately 85mbs each. Loading each one and saving often creates issues.

Any assistance would be of a great deal of help