extracting unique rows of data using dplyr

Question

I'm trying to extract only the rows when b is unique value per a.

Here is some sample data

a <- c(1,1,2,2,3,3,4,4,5,5,5,6,6,7,7,8,8,9,9,9,9,9,10,10,10)
b <- c(1,2,1,1,5,5,6,1,1,1,3,2,2,1,1,2,3,1,2,3,4,4,1,2,2)
df1 <- data.frame(a, b)

and using the dplyr package

library(dplyr)

Unique <- df1 %>%
  group_by(a) %>%
  filter(n_distinct(b))

The desired output should be a data frame length 18

does it have to be with dplyr? `unique(df1)` already does that and is a lot faster — JeremyS, Mar 17 '16 at 08:50

akrun · Answer 1 · 2016-03-17T08:50:24.700

5

We can try

library(dplyr)
df1 %>%
    distinct()

Or in base R

unique(df1)

edited Mar 17 '16 at 08:50

answered Mar 17 '16 at 08:44

akrun

@mtoto Thanks, but I think the OP want to include `%>%` – akrun Mar 17 '16 at 08:51

1 Answers1