Let's say I have the following data.frame:
df <- structure(list(a = c(1, 1, 1, 4), b = c(2, 2, 3, 4), c = c("a",
"b", "c", "d")), .Names = c("a", "b", "c"), row.names = c(NA,
-4L), class = "data.frame")
> df
# a b c
# 1 1 2 a
# 2 1 2 b
# 3 1 3 c
# 4 4 4 d
if I want to extract get the duplicates considering only columns a and b:
df[duplicated(df[,c(1,2)]),]
# a b c
#2 1 2 b
It is then possible to get the duplicates and the data? Which in this case would be:
#1 1 2 a
#2 1 2 b
