How to add zero columns arbitrary with dates.

I have

a beginning date: surgery_date

And an end date: last_date.

I calculated the total number of months as follows:

    date1 = datevec(surgery_date, 'dd-mmm-yy')
    date2 = datevec(last_date, 'dd-mmm-yy')

    % This if/else checks which date is later than the other
    if(datenum(date1) > datenum(date2))
        % num months is the number of months left in date2's year (ex. 2 months)+
        % the number of months in date1's year (ex. 6 months) +
        % the number of months in the years between (ex. 0 months).
        num_months = (12 - date2(2)) +  date1(2) + 12*(date1(1)-date2(1)-1)
    else
        %just flipped date1 and date2 from the above.
        num_months = (12 - date1(2)) + date2(2) + 12*(date2(1)-date1(1)-1) 
    end

So num_months will give me the total number of months from surgery_date to last_date.

The data I have between these two dates is only at certain months arbitrary. So what I need to do is, start from my sugery_date and look at each next month if there is data available, if not add a column of zeros under month 1,2,3 (which ever does not have data) from the surgery date.

[Roger Wohlwend]

All I see in your code is that you calculate the number of months between two dates. Where do you want to add a column of zeros?

By the way ... you could simplify your formula:

num_month = date1(2) - date2(2) + 12*(date1(1) - date2(1));