Filter or subsetting rows in R using Dplyr

In this article, we are going to filter the rows from dataframe in R programming language using Dplyr package.

Dataframe in use:

Method 1: Subset or filter a row using filter()

To filter or subset row we are going to use the filter() function.

Syntax:

filter(dataframe,condition)

Here, dataframe is the input dataframe, and condition is used to filter the data in the dataframe

Example: R program to filter the data frame 

R

# load the package
library(dplyr)

# create the dataframe with three columns
# id , department and salary with 8 rows
data=data.frame(id=c(7058,7059,7060,7089,7072,7078,7093,7034),

                department=c('IT','sales','finance','IT','finance',
                             'sales','HR','HR'),

                salary=c(34500.00,560890.78,67000.78,25000.00,
                         78900.00,25000.00,45000.00,90000))

#display actual  dataframe
print(data)
print("==========================")

#filter dataframe with department is sales
print(filter(data,department=="sales"))

Output:

Method 2: Filter dataframe with multiple conditions

 We are going to use the filter function to filter the rows. Here we have to specify the condition in the filter function.

Syntax:

filter(dataframe,condition1condition2,.condition n)

Here, dataframe is the input dataframe and conditions is used to filter the data in the dataframe

Example: R program to filter multiple rows

R

# load the package
library(dplyr)

# create the dataframe with three columns
# id , department and salary with 8 rows
data=data.frame(id=c(7058,7059,7060,7089,7072,7078,7093,7034),

                department=c('IT','sales','finance','IT','finance',
                             'sales','HR','HR'),

                salary=c(34500.00,560890.78,67000.78,25000.00,
                         78900.00,25000.00,45000.00,90000))

# display actual  dataframe
print(data)
print("==========================")

# filter dataframe with department is sales and
# salary is greater than 27000
print(filter(data,department=="sales" & salary >27000))

Output:

Example: Filter rows by OR operator

R

# load the package
library(dplyr)

# create the dataframe with three columns
# id , department and salary with 8 rows
data=data.frame(id=c(7058,7059,7060,7089,7072,7078,7093,7034),

                department=c('IT','sales','finance','IT','finance',
                             'sales','HR','HR'),

                salary=c(34500.00,560890.78,67000.78,25000.00,
                         78900.00,25000.00,45000.00,90000))

# display actual  dataframe
print(data)
print("==========================")

# filter dataframe with department is IT or salary
# is greater than 27000
print(filter(data,department=="IT" |  salary >27000))

Output:

Example: R program to filter using and, or

R

# load the package
library(dplyr)

# create the dataframe with three columns
# id , department and salary with 8 rows
data=data.frame(id=c(7058,7059,7060,7089,7072,7078,7093,7034),

                department=c('IT','sales','finance','IT','finance',
                             'sales','HR','HR'),

                salary=c(34500.00,560890.78,67000.78,25000.00,
                         78900.00,25000.00,45000.00,90000))

# display actual  dataframe
print(data)
print("==========================")

# filter dataframe with department is sales
# and salary is greater than 27000 or salary
# less than 5000
print(filter(data,department=="sales" & salary >27000 | salary<5000))

Output:

Method 3: Using slice_head() function

This function is used to get top n rows from the dataframe.

Syntax:

dataframe %>% slice_head(n)

where, dataframe is the input dataframe, %>% is the operator (pipe operator) that loads the dataframe and n is the number of rows to be displayed.

Example: R program that used slice_head() to filter rows

R

# load the package
library(dplyr)

# create the dataframe with three columns
# id , department and salary with 8 rows
data=data.frame(id=c(7058,7059,7060,7089,7072,7078,7093,7034),

                department=c('IT','sales','finance','IT','finance',
                             'sales','HR','HR'),

                salary=c(34500.00,560890.78,67000.78,25000.00,
                         78900.00,25000.00,45000.00,90000))

# display actual  dataframe
print(data)
print("==========================")

# display top 3 values with slice_head
data %>% slice_head(n=3)
print("==========================")

# display top 5 values with slice_head
data %>% slice_head(n=5)
print("==========================")

# display top 1 value  with slice_head
data %>% slice_head(n=1)

Output:

Method 4: Using slice_tail() function

This function is used to get last  n rows from the dataframe

Syntax:

dataframe %>% slice_tail(n)

Where, dataframe is the input dataframe, %>% is the operator (pipe operator) that loads the dataframe and n is the number of rows to be displayed from last

Example: R program to filter last rows by using slice_tail() method

R

# load the package
library(dplyr)

# create the dataframe with three columns
# id , department and salary with 8 rows
data=data.frame(id=c(7058,7059,7060,7089,7072,7078,7093,7034),

                department=c('IT','sales','finance','IT','finance',
                             'sales','HR','HR'),

                salary=c(34500.00,560890.78,67000.78,25000.00,
                         78900.00,25000.00,45000.00,90000))

# display actual  dataframe
print(data)
print("==========================")

# display last 3 values with slice_tail
data %>% slice_tail(n=3)
print("==========================")


# display last 5 values with slice_tail
data %>% slice_tail(n=5)
print("==========================")

# display last 1 value  with slice_tail
data %>% slice_tail(n=1)

Output:

Method 5: Using top_n() function

This function is used to get top n rows.

Syntax:

data %>% top_n(n=5)

Example: R program that filter rows using top_n() function

R

# load the package
library(dplyr)

# create the dataframe with three columns
# id , department and salary with 8 rows
data=data.frame(id=c(7058,7059,7060,7089,7072,7078,7093,7034),

                department=c('IT','sales','finance','IT','finance',
                             'sales','HR','HR'),

                salary=c(34500.00,560890.78,67000.78,25000.00,78900.00,
                         25000.00,45000.00,90000))

# display actual  dataframe
print(data)
print("==========================")

# display last 3 values with top_n
data %>% top_n(n=3)
print("==========================")

# display last 5 values with top_n
data %>% top_n(n=5)
print("==========================")

# display last 1 value  with top_n
data %>% top_n(n=1)

Output:

Method 6: Using slice_sample() function

Here, we are going to filter rows using the slice_sample() function, this will return sample n rows randomly

Syntax:

slice_sample(n)

Example: R program to filter rows using slice_sample () function

R

# load the package
library(dplyr)

# create the dataframe with three columns
# id , department and salary with 8 rows
data=data.frame(id=c(7058,7059,7060,7089,7072,7078,7093,7034),

                department=c('IT','sales','finance','IT','finance',
                             'sales','HR','HR'),

                salary=c(34500.00,560890.78,67000.78,25000.00,
                         78900.00,25000.00,45000.00,90000))

# display actual  dataframe
print(data)
print("==========================")

# display last 3 values with slice_sample
data %>% slice_sample(n=3)
print("==========================")

# display last 5 values with slice_sample
data %>% slice_sample(n=5)
print("==========================")

# display last 1 value  with slice_sample
data %>% slice_sample(n=1)

Output:

Method 7: Using slice_max() function

This function returns the maximum n rows of the dataframe based on a column 

Syntax:

dataframe %>% slice_max(column, n )

Where dataframe is the input dataframe, the column is the dataframe column where max rows are returned based on this column and n is the number of maximum rows to be returned

Example: R program to filter using slice_max() function

R

# load the package
library(dplyr)

# create the dataframe with three columns
# id , department and salary with 8 rows
data=data.frame(id=c(7058,7059,7060,7089,7072,7078,7093,7034),

                department=c('IT','sales','finance','IT','finance',
                             'sales','HR','HR'),

                salary=c(34500.00,560890.78,67000.78,25000.00,
                         78900.00,25000.00,45000.00,90000))

# display actual  dataframe
print(data)
print("==========================")

# return top 3 maximum rows based on salary
# column in the dataframe
print(data %>% slice_max(salary, n = 3))
print("==========================")

# return top 5 maximum rows based on department
# column in the dataframe
print(data %>% slice_max(department, n = 5))
print("==========================")

Output:

Method 8: Using slice_min() function

This function returns the minimum n rows of the dataframe based on a column

Syntax:

dataframe %>% slice_min(column, n )

Where dataframe is the input dataframe, the column is the dataframe column where max rows are returned based on this column and n is the number of minimum rows to be returned

Example: R program to filter using slice_min()

R

# load the package
library(dplyr)

# create the dataframe with three columns
# id , department and salary with 8 rows
data=data.frame(id=c(7058,7059,7060,7089,7072,7078,7093,7034),

                department=c('IT','sales','finance','IT','finance',
                             'sales','HR','HR'),

                salary=c(34500.00,560890.78,67000.78,25000.00,
                         78900.00,25000.00,45000.00,90000))

# display actual  dataframe
print(data)
print("==========================")

# return top 3 minimum rows based on salary
# column in the dataframe
print(data %>% slice_min(salary, n = 3))
print("==========================")

# return top 5 minimum rows based on department
# column in the dataframe
print(data %>% slice_min(department, n = 5))
print("==========================")

Output:

Method 9: Using sample_frac() function

The sample_frac() function selects a random n percentage of rows from a data frame (or table). First parameter contains the data frame name, the second parameter tells what percentage of rows to select

Syntax:

(sample_frac(dataframe,n)

Where dataframe is the input dataframe and n is the fraction value

Example: R program to filter data using sample_frac() function

R

# load the package
library(dplyr)

# create the dataframe with three columns
# id , department and salary with 8 rows
data=data.frame(id=c(7058,7059,7060,7089,7072,7078,7093,7034),

                department=c('IT','sales','finance','IT','finance',
                             'sales','HR','HR'),

                salary=c(34500.00,560890.78,67000.78,25000.00,
                         78900.00,25000.00,45000.00,90000))

# display actual  dataframe
print(data)
print("==========================")

# return 2 rows
print(sample_frac(data,0.2))
print("==========================")

# return 4 rows
print(sample_frac(data,0.4))
print("==========================")

# return 7 rows
print(sample_frac(data,0.7))
print("==========================")

Output: