Remove rows from a data frame that exists in another data frame in R.

To remove rows from a data frame that exists in another data frame, we can use subsetting with single square brackets. This removal will help us to find the unique rows in the data frame based on the column of another data frame.

Check out the below Examples to understand how it can be done.

Example 1

Following snippet creates a sample data frame −

x
The following dataframe is created
   x y
1  2 0
2  1 2
3  1 3
4  2 1
5  0 0
6  3 3
7  1 3
8  0 2
9  3 2
10 2 0
11 2 1
12 1 6
13 1 2
14 2 1
15 4 5
16 2 2
17 1 4
18 0 1
19 0 1
20 2 2
Add the following code to the above snippet −
x
The following dataframe is created
   a b
1  4 0
2  3 6
3  4 6
4  1 3
5  5 3
6  5 7
7  5 2
8  4 6
9  4 6
10 4 3
11 3 6
12 4 4
13 4 2
14 5 2
15 4 3
16 3 7
17 4 6
18 5 3
19 3 3
20 9 3
To remove rows in df1 based on column x that do not exist in column a of df2 on the
above created data frame, add the following code to the above snippet −
x
Output
If you execute all the above given snippets as a single program, it generates the following Output −
   x y
1  2 0
4  2 1
5  0 0
8  0 2
10 2 0
11 2 1
14 2 1
16 2 2
18 0 1
19 0 1
20 2 2
Example 2
Following snippet creates a sample data frame −
Grp
The following dataframe is created
 Grp Rate
1  D 6
2  D 3
3  E 7
4  D 6
5  B 6
6  D 3
7  D 3
8  A 3
9  C 2
10 A 4
11 A 7
12 C 7
13 C 5
14 E 7
15 B 7
16 C 6
17 B 6
18 A 4
19 C 6
20 B 1
Add the following code to the above snippet −
Grp
The following dataframe is created
Category Sales
1    E    12
2    C    11
3    D     9
4    E    13
5    G     5
6    C     9
7    D    14
8    D    11
9    D     8
10   F    11
11   F    17
12   G    15
13   F    12
14   D     9
15   G    13
16   C     9
17   C    12
18   F     7
19   E     7
20   C     8
To remove rows in df_grp based on column Grp that do not exist in column Category of
df_Sales on the above created data frame, add the following code to the above snippet −
Grp
Output
If you execute all the above given snippets as a single program, it generates the following Output −
Grp  Rate
5  B 6
8  A 3
10 A 4
11 A 7
15 B 7
17 B 6
18 A 4
20 B 1