Remove duplicated rows (based on 2 columns) in R

Question

I have a dataset in R which looks like this:

    x1 x2  x3
1:  A Away  2
2:  A Home  2
3:  B Away  2
4:  B Away  1
5:  B Home  2
6:  B Home  1
7:  C Away  1
8:  C Home  1

Based on the values in columns x1 and x2, I want to remove the duplicate rows. I have tried the following:

df[!duplicated(df[,c('x1', 'x2')]),]

It should remove rows 4 and 6. But unfortunately it is not working, as it returns exactly the same data, with the duplicates still present in the dataset. What do I have to use in order to remove rows 4 and 6?

Answer 1

I'd just do:

unique(df, by=c("x1", "x2")) # where df is a data.table

This'd have been quite obvious if you'd just looked at ?unique.

PS: given the syntax in your Q, I wonder if you are aware of the basic differences between data.table and data.frame's syntax. I suggest you read the vignettes first.