Extending Ari's answer, to specify columns to check if other columns are also there:
a <- c(rep("A", 3), rep("B", 3), rep("C",2))
b <- c('A','B','B','C','A','A','B','B')
df <-data.frame(a,b)
df$c = sample(1:10,8)
df$d = sample(LETTERS,8)
df
a b c d
1 A A 10 B
2 A B 8 S
3 A B 7 J
4 B C 3 Q
5 B A 2 I
6 B A 6 U
7 C B 4 L
8 C B 5 V
cols = c(1,2)
newdf = df[,cols]
for (i in 1:nrow(df)){
newdf[i, ] = sort(df[i,cols])
}
df[!duplicated(newdf),]
a b c d
1 A A 8 X
2 A B 7 L
4 B C 2 P
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