identify number of duplicates

[yoyong]

Hi.

I have a large dataset with two columns - ID and Status. I want to create a table to know how many observations are unique, 1 duplicate, 2 duplicates, 3 duplicates and so on...How will the code look like?

Thanks.

yoyong

[FJCC]

I think you want to use the table() function. Here is an example. The numbers in the table show how many times each combination occurs.

DF <- data.frame(ID = c("A", "C", "B", "A", "B", "C", "C", "B"),
                  Status = c(2,3,1,3,2,1,3,2))
DF
  ID Status
1  A      2
2  C      3
3  B      1
4  A      3
5  B      2
6  C      1
7  C      3
8  B      2

table(DF$ID, DF$Status)
   
    1 2 3
  A 0 1 1
  B 1 2 0
  C 1 0 2