Joining Data in R with Dplyr Package

In this article, we will be looking at the different methods of joining data with the dplyr in the R programming language.

We need to load the dplyr package. Type the below commands –

Install - install.packages("dplyr")          
Load - library("dplyr") 

Method 1: Using  inner join 

In this method of joining data,  the user call the inner_join function, which will result to jointed data with the records that have matching values in both tables in the R programming language. 

inner_join() function:

This function includes all rows in `x` and `y`. 

Syntax:

inner_join(x, y, by = NULL, on = NULL)

Parameters:

• x: A data.table
• y: A data.table
• by: A character vector of variables to join by.
• on: Indicate which columns in x should be joined with which columns in y.

Example:

In this example, we will be using the inner_join() function from the dplyr package to join two different data as shown in the image above in the R programming language.

R

# load the library
library("dplyr")

# create dataframe with 1 to 5 integers
gfg1 < -data.frame(ID=c(1: 5))

# create dataframe with 4 to 8 integers
gfg2 < -data.frame(ID=c(4: 8))

# perform inner join
inner_join(gfg1, gfg2, by="ID")

Output:

 ID
1 4
2 5 

Method 2: Using  left join

In this method of joining data,  the user call the left_join function and this will result to jointed data consisting of matching all the rows in the first data frame with the corresponding values on the second.s in the R programming language.

left_join() function:

This function includes all rows in `x`. 

Syntax:

left_join(x, y, by = NULL, on = NULL)

Parameters:

• x: A data.table
• y: A data.table
• by: A character vector of variables to join by.
• on: Indicate which columns in x should be joined with which columns in y.

Example:

In this example, we will be using the left_join() function from the dplyr package to join two different data as shown in the image above in the R programming language.

R

# load the library
library("dplyr")

# create the dataframes
gfg1<-data.frame(ID=c(1:5))

gfg2<-data.frame(ID=c(4:8))

# perform left join
left_join(gfg1,gfg2, by = "ID")

Output:

  ID
1  1
2  2
3  3
4  4
5  5

Method 3: Using  right join

In this method of joining data, the user call the right_join function and this will result to jointed data consisting of matching all the rows in the second data frame with the corresponding values on the first in the R programming language.

right_join() function:

This function includes all rows in `y` and corresponding rows of ‘x’.

Syntax:

right_join(x, y, by = NULL, on = NULL)

Parameters:

• x: A data.table
• y: A data.table
• by: A character vector of variables to join by.
• on: Indicate which columns in x should be joined with which columns in y.

Example:

In this example, we will be using the right_join() function from the dplyr package to join two different data as shown in the image above in the R programming language.

R

# load the library
library("dplyr")

# create dataframes
gfg1<-data.frame(ID=c(1:5))

gfg2<-data.frame(ID=c(4:8))

# perform right join
right_join(gfg1,gfg2, by = "ID")

Output:

  ID
1  4
2  5
3  6
4  7
5  8

Method 4: Using full join

In this method of joining data,  the user calls the right_join function and  this will result in jointed data  of all the rows from the joined tables,

full_join() function:

This function includes all rows.

Syntax:

full_join(x, y, by = NULL, on = NULL)

Parameters:

• x: A data.table
• y: A data.table
• by: A character vector of variables to join by.
• on: Indicate which columns in x should be joined with which columns in y.

Example:

In this example, we will be using the full_join() function from the dplyr package to join two different data as shown in the image above in the R programming language.

R

# load library
library("dplyr")

# create dataframe
gfg1<-data.frame(ID=c(1:5))
gfg2<-data.frame(ID=c(4:8))

# perform full join
full_join(gfg1,gfg2, by = "ID")

Output:

  ID
1  1
2  2
3  3
4  4
5  5
6  6
7  7
8  8

Method 5: Using Semi join

In this method of joining data, the user calls the right_join function and this will return one copy of each row in the first table for which at least one match is found.

semi_join() function:

This function returns all rows from x where there are matching values in y, keeping just columns from x..

Syntax:

semi_join(x, y, by = NULL, on = NULL)

Parameters:

• x: A data.table
• y: A data.table
• by: A character vector of variables to join by.
• on: Indicate which columns in x should be joined with which columns in y.

Example:

In this example, we will be using the semi_join() function from the dplyr package to join two different data as shown in the image above in the R programming language.

R

# load the library
library("dplyr")

# create the dataframes
gfg1<-data.frame(ID=c(1:5))
gfg2<-data.frame(ID=c(4:8))

# perform semijoin
semi_join(gfg1,gfg2, by = "ID")

Output:

  ID
1  4
2  5

Method 6:  Using anti join

In this method of joining data, the user calls the right_join function and this will return all rows from x where there are no matching values in y, keeping just columns from x.

anti_join() function:

This function returns all rows from x where there are no matching values in y, keeping just columns from x.

Syntax:

anti_join(x, y, by = NULL, on = NULL)

Parameters:

• x: A data.table
• y: A data.table
• by: A character vector of variables to join by.
• on: Indicate which columns in x should be joined with which columns in y.

Example:

In this example, we will be using the anti_join() function from the dplyr package to join two different data as shown in the image above in the R programming language.

R

# load the library
library("dplyr")

# create the dataframes
gfg1<-data.frame(ID=c(1:5))
gfg2<-data.frame(ID=c(4:8))

# perform anti join
anti_join(gfg1,gfg2, by = "ID")

Output:

  ID
1  1
2  2
3  3