How can I remove duplicate rows from this example data frame?
A 1
A 1
A 2
B 4
B 1
B 1
C 2
C 2
I would like to remove the duplicates based on both the columns:
A 1
A 2
B 4
B 1
C 2
Order is not important.
$\begingroup$
$\endgroup$
2
-
$\begingroup$ @whuber shouldn't that be moved to SO? $\endgroup$– llrsCommented Mar 31, 2017 at 9:55
-
$\begingroup$ @Llopis Yes, but it's too late to do that now--and it was too late when we originally closed it. This kind of question was considered (borderline) on-topic many years ago but nowadays it would be migrated quickly. $\endgroup$– whuber ♦Commented Mar 31, 2017 at 14:12
Comments disabled on deleted / locked posts / reviews
|
2 Answers
$\begingroup$
$\endgroup$
1
unique() indeed answers your question, but another related and interesting function to achieve the same end is duplicated().
It gives you the possibility to look up which rows are duplicated.
a <- c(rep("A", 3), rep("B", 3), rep("C",2))
b <- c(1,1,2,4,1,1,2,2)
df <-data.frame(a,b)
duplicated(df)
[1] FALSE TRUE FALSE FALSE FALSE TRUE FALSE TRUE
> df[duplicated(df), ]
a b
2 A 1
6 B 1
8 C 2
> df[!duplicated(df), ]
a b
1 A 1
3 A 2
4 B 4
5 B 1
7 C 2
-
2$\begingroup$ Thanks for mentioning the 'duplicated' function. It can be used to delete duplicated rows based on a subset of the columns. $\endgroup$– JokoCommented Jan 20, 2016 at 15:27
$\begingroup$
$\endgroup$
1
You are looking for unique().
a <- c(rep("A", 3), rep("B", 3), rep("C",2))
b <- c(1,1,2,4,1,1,2,2)
df <-data.frame(a,b)
unique(df)
> unique(df)
a b
1 A 1
3 A 2
4 B 4
5 B 1
7 C 2
-
1$\begingroup$ Thanks Bernd. I thought unique can be applied only for a specific column. I didn't know that it can be used for the entire data frame as well. thanks again $\endgroup$– JanaCommented Jan 31, 2011 at 20:25