Missing Rows from Dataset in R

Question

I have spent the better part of yesterday afternoon and this morning trying to gain some insight into my issue. If you can point me to any resources that would be great!

I have a dataframe in R (imported from an Oracle table), see the data below. I call it Loss_Data.

    Loss_Yr Dev_Lag Claim_Amnt
1   2007    1   300
2   2007    2   10
3   2007    3   250
4   2007    5   5
5   2008    1   450
6   2008    2   80
7   2008    4   3
8   2009    1   175
9   2009    3   20
10  2010    1   95
11  2010    2   40
12  2011    1   130

However, I need to get it to look like the following. I need to make sure that there is a row for every possible Loss_Yr and Dev_Lag combination. See the added rows

    Loss_Yr Dev_Lag Claim_Amnt
1   2007    1   300
2   2007    2   10
3   2007    3   250
***4    2007    4   0***
5   2007    5   5
6   2008    1   450
7   2008    2   80
***8    2008    3   0***
9   2008    4   3
10  2009    1   175
***11   2009    2   0***
12  2009    3   20
13  2010    1   95
14  2010    2   40
15  2011    1   130

At first I was thinking that I would create a "dummy" table with all possible combinations and then do a merge with my existing; keeping the records from my intial table, Loss_Data.

However, I am trying to build a process and this method wouldn't be very felxible.

Any ideas on how to tackle this?!

Answer 1

The approach you describe is the right idea. Maybe you're over-complicating the implementation?

d <- read.table(text="Loss_Yr Dev_Lag Claim_Amnt
1   2007    1   300
2   2007    2   10
3   2007    3   250
4   2007    5   5
5   2008    1   450
6   2008    2   80
7   2008    4   3
8   2009    1   175
9   2009    3   20
10  2010    1   95
11  2010    2   40
12  2011    1   130", header=TRUE, row.names=1)

filled <- merge(d, 
                with(d, expand.grid(Loss_Yr=unique(Loss_Yr), Dev_Lag=unique(Dev_Lag))), 
                all=TRUE)