How to keep the true uniques row?

Question

Here an example of a matrix,

A	B	C
1	1	1
1	1	4
1	2	4
2	1	1
3	1	1
3	1	2

I would like extract only rows which are unique in A and B. I can't use unique, duplicate etc. because they retain always one of my duplicated row.

In final result I wish obtain:

A	B	C
1	2	4
2	1	1

How can I do it? Thank you

Answer 1

Here are couple of options -

1. Base R -

cols <- c('A', 'B')
res <- df[!(duplicated(df[cols]) | duplicated(df[cols], fromLast = TRUE)), ]
res

#  A B C
#3 1 2 4
#4 2 1 1

2. dplyr -

library(dplyr)
df %>% group_by(A, B) %>% filter(n() == 1) %>% ungroup

# A tibble: 2 x 3
#      A     B     C
#  <int> <int> <int>
#1     1     2     4
#2     2     1     1