Question

How can I remove duplicated rows in R

Answer 1

The function distinct() in the dplyr package performs arbitrary duplicate removal

Data:

dt <- data.frame(m = rep(c(1,2),4), n = rep(LETTERS[1:4],2))

Remove rows where specified columns have been duplicated:

library(dplyr)
dat %>% distinct(m, .keep_all = TRUE)

  m n
1 1 A
2 2 B

Remove rows which are complete duplicates of other rows:

dat %>% distinct

  m n
1 1 A
2 2 B
3 1 C
4 2 D

Generaleneral answer for duplicate row removal

m <- c(rep("A", 3), rep("B", 3), rep("C",2))
n <- c(1,1,2,4,1,1,2,2)
df <-data.frame(m,n)

duplicated(df)
[1] FALSE  TRUE FALSE FALSE FALSE  TRUE FALSE  TRUE

df[duplicated(df), ]
  m n
2 A 1
6 B 1
8 C 2

df[!duplicated(df), ]
  m n
1 A 1
3 A 2
4 B 4
5 B 1
7 C 2