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dplyr in R I Data Wrangling Made Easy in 5 Steps

Data wrangling with dplyr in R for efficient and comprehensive data analysis. Learn powerful data manipulation techniques, and much more.

How often do you struggle with data wrangling? Do you know dplyr in R makes it easy? If you are like most data analysts, you spend more time cleaning, transforming, and manipulating data than actually analyzing it. But what if there was a way to make data wrangling easier, faster, and more fun? That’s where dplyr comes in. 

Learn dplyr in R for Effortless Data Wrangling

Dplyr is a powerful package in R that provides a consistent and intuitive syntax for data manipulation in R. It allows you to perform common tasks such as filtering, grouping, summarizing, joining, and reshaping data with just a few lines of code. Dplyr also works seamlessly with other packages in the tidyverse, such as tidyr, ggplot2, and readr, to create a comprehensive data analysis workflow.

Key Takeaways

  • Dplyr is a handy tool for doing various kinds of data wrangling quickly and easily. 
  • Dplyr functions run faster than base R functions because they were coded computationally efficiently. Dplyr functions are also more consistent in syntax and work better with data frames than vectors.
  • It is particularly good for making summary tables for different groups of data. 
  • You can chain multiple pipes together so that the result of one function becomes the input of another. 
  • The dplyr code enables function chaining, which avoids any possible messiness in the code and makes it easier to write and read. 
dplyr in R I Data Wrangling Made Easy in 10 Steps
Table of Contents

How to install dplyr in r studio

Before we learn how to perform data manipulation tasks using complex and large data frames, we must install the latest Rstudio and R language or programming version. If you need to learn how to install it, read it here: Rstudio.

Install and Load the dplyr in R, RStudio

Use the code below to install the dplyr package. Once the installation is finished, we can load the package into our RStudio session using the library() function. 

install.packages("dplyr")
library(dplyr)
How to Install and Load the dplyr in R, RStudio

How to use dplyr in R 

Dplyr is a package for data manipulation in R. It has functions that help you do common tasks like selecting, filtering, arranging, mutating, summarizing, and joining data. You can use dplyr with data frames and tibbles and other data sources like databases and Apache Spark. 

You can chain multiple dplyr functions using the pipe operator %>%. Dplyr makes data wrangling easier, faster, and more fun. read more 

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How to Load data in r

Before we start with data wrangling using dplyr in R, we must start by loading our data in RStudio. The dplyr in R package offers incredible versatility, enabling us to work seamlessly with various data sources, including data frames, databases, and CSV files. This example demonstrates how to import data from a CSV file named "mtcars".

data(mtcars) # load the mtcars data in r
names(mtcars) # Variables names of mtcars data in r
head(mtcars) # top five rows of the mtcars data in r
str(mtcars) # structure of the data
Load the mtcars data in R, then view the names, top fives rows of data using head function and then view the structure of the data using str function

mtcars Data in R

The mtcars data in r is a dataset that contains information about 32 cars from various models and manufacturers. It has 11 numeric variables measuring car aspects, such as mileage, engine size, power, weight, speed, and transmission type. 

The dataset is useful for exploring the relationship between these variables and the performance of the cars. The dataset is also a good example of using the dplyr package for data manipulation in R. read more

How to use select() function in dplyr?

Often, you only need a few columns when working with a dataset. With the help of the select() function in dplyr, you can easily select the columns you want to analyze. You can do this by specifying the column names directly or using certain conditions. Let's say we want to get the information about 'name' and 'age' from our dataset.

selected_data<- mtcars %>% select(-carb) # Remove irrelevant column, using dplyr
names(selected_data) # check column was removed
How to use select() function in dplyr remove the carb column from mtcars data set in R

How to use the filter in R?

Performing data filtration based on specific conditions is a frequent task in data analytics. The dplyr package's filter() function facilitates the extraction of rows that satisfy particular needs. To apply a filter on the dataset for individuals aged 30 or above, the code snippet below can be utilized:

mtcars %>% filter(mpg <= 20.09) # filter the mpg of mtcars data greater than equal to 20.09
use the filter function from dplyr package in R, to filter mpg of mtcars data greater than equal to 20.09

How to use the arrange function in r dplyr?

Sorting our data based on one or more variables can be achieved using the arrange() function. This function allows us to set our data in ascending or descending order. To sort our data by the "mpg" column in descending order, we can use the following code:

# Arranging Data with arrange()
mtcars %>%  arrange( desc(mpg))
Arrange the data based on mpg data set of mtcars in R by using the arrange function in dplyr r

How to create a new variable in r based on condition dplyr? 

While doing data analysis, creating new variables in r may be necessary based on the condition. Then, the mutate function in r dplyr comes in handy. The mutate() function within the dplyr package facilitates creating columns or altering pre-existing ones. 

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Assuming the objective is to calculate the ratio of mpg and hp, it can be calculated by using the below code: 

# Creating New Variables with mutate()
mtcars %>%   mutate( ratio = mpg / hp)
to calculate the ratio of mpg and hp using the mutate function r dplyr

How to use summarize in r with dplyr?

Summarization of data is a crucial step towards gaining valuable insights from it. The dplyr packages summarize() function facilitates the computation of diverse summary statistics, including but not limited to mean, median, minimum, and maximum. Below is an illustration of computing the mean salary from our dataset:

# Average mpg and hp using summarize function of dplyr in R 
mtcars %>% summarize(average_mpg = mean(mpg),
                     average_hp = mean(hp))
Average mpg and hp using summarize function of dplyr in R

Group by and summarize in r dplyr

The process of grouping a data frame by one or more variables and then calculating summary statistics for each group using the dplyr package.

For example, using the mtcars data set, we can group the cars by the number of cylinders (cyl) and then calculate the average miles per gallon (mpg) and the standard deviation of horsepower (hp) for each group:

mtcars %>% group_by(cyl) %>% summarize(avg_mpg = mean(mpg), sd_hp = sd(hp))
Descriptive statistics using the summarize function of dplyr package in Rstudio

summarize categorical data in r dplyr

For example, using the mtcars data set, we can summarize the number and proportion of cars with automatic (0) or manual (1) transmission (am):

mtcars %>% group_by(am) %>% summarize(count = n(), prop = n() / nrow(mtcars))
sing the mtcars data set, we can summarize the number and proportion of cars with automatic (0) or manual (1) transmission (am) using the dplyr in R

We can also summarize the number and proportion of cars with different combinations of transmission (am) and engine shape (vs):

mtcars %>% group_by(am, vs) %>% summarize(count = n(), prop = n() / nrow(mtcars))
summarize the number and proportion of cars with different combinations of transmission  by using summarize function of dplyr in R

How to change the column name in r dplyr? 

One way to do this is to use the rename () function, which takes a data frame and a named list of new and old column names. For example, to change the column name “mpg” to “miles_per_gallon” in the mtcars data set, we can use the following code:

mtcars %>% select(mpg) %>% 
  rename(miles_per_gallon = mpg) %>% 
  head(n=10)
Rename the mpg column from mtcars data set using the rename function from dplyr package in R

How to use the rename_with function to make it upper class in r dplyr?

One way to do this is to use the rename_with () function, which takes a data frame, a function to apply to the column names, and a selection of columns to rename. For example, to convert all column names to uppercase in the mtcars data set, we can use the following code:

mtcars %>% rename_with(toupper)%>% 
  head(n=10)
the rename_with function to make it upper class in r dplyr

How to merge multiple data frames in r dplyr? 

Different types of joins can be performed using the dplyr package, such as: 

  • Inner join, 
  • left join, 
  • right join, 
  • full join, 
  • semi join, 
  • anti join. 
Each join has a corresponding function that takes two data frames and a specification of the variables to join by. For example, to perform a left join of the mtcars and iris data sets by the variable “cyl” in mtcars and “sepal.width” in iris, we can use the following code:

mtcars %>% 
  left_join(iris, by = c("cyl" = "Sepal.Width")) %>% 
  head(n=5)
by using the left_join, merge the two data frame mtcars and iris data set by using the cyl and speal width column

How to use dplyr inner join in r?

A join is a way of combining two data frames by matching rows based on common variables. The dplyr package provides various join functions that perform various types of joins. Each join function takes two data frames and a specification of the variables to join by. 

For example, to perform an inner join of the mtcars and iris data sets by the variable “cyl” in mtcars and “Sepal.Width” in iris, we can use the following code:

mtcars %>% 
  inner_join(iris, by = c("cyl" = "Sepal.Width")) %>% 
  head(n=5)
Combine cyl and sepal width from mtcars and iris data set in r by using the  dplyr inner join in r

How to replace values in r dplyr? 

Replacing specific values in a data frame or a vector with new values using the dplyr package. One way to do this is to use the mutate () and replace () functions, which take a data frame or a vector, a condition to identify the values to replace, and the new values to use. 

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For example, to replace all values of 4 in the “cyl” column of the mtcars data set with 99, we can use the following code:

mtcars %>% select(cyl) %>% 
  mutate(cyl = replace(cyl, cyl == 4, 99))%>% 
  head(n=5)
replace the cyl value of 4 with 99, using mtcars in R by replace values in r dplyr

How to replace na in specific column r dplyr?

We will use the mutate () and ifelse () functions, which take a data frame, a column name, a condition to identify the missing values, and the new value to use. For example, to replace all NA values in the “mpg” column of the mtcars data set with 0, we can use the following code:

set.seed(123) # for reproducibility
z<-mtcars %>% mutate(mpg = replace(mpg, sample(1:n(), 5), NA))
names(which(colSums(is.na(z)) > 0))
z %>% mutate(mpg = ifelse(is.na(mpg), 0, mpg))%>% 
  head(n=5)
Replace the missing value with zero by using the mutate function from dplyr in R

How to use the summary table in r dplyr? 

The group_by () and summarise () functions take a data frame, grouping variables, and one or more summary functions. For example, to create a table that shows the mean and standard deviation of “mpg” for each level of “cyl” in the mtcars data set, we can use the following code:

mtcars %>% group_by(cyl) %>% summarise(mean_mpg = mean(mpg), sd_mpg = sd(mpg))
group_by () and summarise () functions take a data frame, grouping variables, and one or more summary functions.

Best Practices for Efficient Data Wrangling

Data wrangling is the process of transforming raw data into a clean and tidy format that is suitable for analysis and visualization. Data wrangling can be challenging and time-consuming, especially when dealing with large and complex datasets. Fortunately, R offers a powerful package for data manipulation and wrangling: dplyr.

Dplyr is part of the tidyverse, which provides a grammar of data manipulation that consists of verbs, such as select, filter, arrange, mutate, summarize, and join. These verbs allow you to perform common tasks such as selecting, filtering, sorting, creating, modifying, aggregating, and combining data with just a few lines of code.

To use dplyr effectively, here are some best practices to follow:

  • Use the pipe operator (%>%) to combine multiple dplyr functions and create readable and elegant code.
  • Use the group_by() function to perform grouped operations and calculations on data.
  • Use the across() function to apply functions across multiple columns simultaneously.
  • Use the join() functions to merge data from different sources based on common variables.
  • Use the pivot_longer() and pivot_wider() functions from tidyr to reshape your data from wide to long format and vice versa.
  • Please ensure your code is properly documented and includes comments that clearly and concisely explain the code's functionality. This will aid in the understanding and maintenance of the codebase.

Conclusion

This guide provides an in-depth analysis of the capabilities of dplyr for streamlined data manipulation and examination within the R programming language. We have explored a range of fundamental operations, such as column selection, data filtering, sorting, variable creation, data summarization, grouping and aggregation, data frame merging, missing value handling, and operation chaining. 

Upon acquiring proficiency in these methodologies, you will possess the essential competencies to address intricate data analytics assignments and extract valuable intelligence from your data repositories.

Frequently Asked Question

What is data wrangling?

Data wrangling refers to cleaning and transforming raw data into a format more suitable for analysis and modeling. It involves removing duplicates, handling missing values, structuring data, and creating new variables.

What is dplyr?

dplyr is an R package that provides functions for efficient data manipulation. It is part of the tidyverse, a collection of R packages for data science.

What common data manipulation tasks can be performed using dplyr?

Some everyday data manipulation tasks that can be performed using dplyr include filtering rows based on conditions, selecting specific columns, arranging data in a specific order, calculating summary statistics, creating new variables, and joining multiple datasets.

How do I install dplyr?

You can install dplyr by running the following command in R: install.packages("dplyr").

What is the pipe operator in dplyr?

The pipe operator (%>%) is a special syntax in dplyr that allows you to chain multiple dplyr functions more readably and expressively. It takes the output of one function and passes it as the first argument to the next function.

How do I select specific rows using dplyr?

You can use the filter() function in dplyr to select specific rows based on conditions. For example, filter(df, column == value) will select the rows where the value in the column equals the specified value.

How do I select specific columns using dplyr?

You can use the select() function in dplyr to select specific columns from a dataframe. For example, select(df, column1, column2) will select only the columns column1 and column2.

How do I create a new variable using dplyr?

You can use the mutate() function in dplyr to create a new variable based on existing variables. For example, mutate(df, new_column = column1 + column2) will create a new column named new_column which is the sum of column1 and column2.

How do I summarize data using dplyr?

You can use the summarise() function in dplyr to calculate summary statistics for specific variables. For example, summarise(df, average = mean(column1)) will calculate the average of column1.

Can I use dplyr with base R functions?

Yes, you can use dplyr with base R functions. dplyr provides a more intuitive and concise syntax for common data manipulation tasks, but you can still use base R functions if needed.

How is dplyr used in data analysis?

dplyr can be used to perform a wide variety of data analysis tasks, such as:

  • Cleaning and preparing data for analysis
  • Exploring and visualizing data
  • Building statistical models
  • Generating reports

What are some of the important dplyr functions?

Some of the most important dplyr functions include:

  • filter(): Select rows from a data frame based on their values
  • select(): Choose columns from a data frame
  • arrange(): Sort rows in a data frame by their values
  • mutate(): Add new columns to a data frame
  • summarize(): Calculate summary statistics for a data frame

How can I use dplyr to select specific columns from a data frame?

To select specific columns from a data frame using dplyr, you can use the select() function. For example, to select the name and age columns from a data frame called df, you would use the following code:

df %>%

select(name, age)

How can I use dplyr to filter rows from a data frame based on their values?

To filter rows from a data frame based on their values using dplyr, you can use the filter() function. For example, to filter the df data frame to only include rows where the age column is greater than 18, you would use the following code:

df %>%

filter(age > 18)

How can I use dplyr to create new columns in a data frame?

To create new columns in a data frame using dplyr, you can use the mutate() function. For example, to create a new column called age_group in the df data frame, where the values are assigned based on the age of the individual, you would use the following code:

df %>%

mutate(age_group = case_when(
age < 18 ~ "Teenager",
age >= 18 & age < 65 ~ "Adult",
age >= 65 ~ "Senior"
))

How can I use dplyr to summarize data in a data frame?

To summarize data in a data frame using dplyr, you can use the summarize() function. For example, to calculate the average age of the individuals in the df data frame, you would use the following code:

df %>%

summarize(average_age = mean(age))

Can I use dplyr to select rows based on the values of two columns?

Yes, you can use dplyr to select rows based on the values of two columns. To do this, you can use the filter() function with a logical expression that combines the values of the two columns. For example, to select rows where the age column is greater than 18 and the gender column is equal to "male", you would use the following code:

df %>%

filter(age > 18 & gender == "male")

Can I use dplyr to create a new column that is the sum of the values of two existing columns?

Yes, you can use dplyr to create a new column that is the sum of the values of two existing columns. To do this, you can use the mutate() function with a mathematical expression that combines the values of the two columns. For example, to create a new column called total_score that is the sum of the math_score and science_score columns, you would use the following code:

df %>%

  mutate(total_score = math_score + science_score) 

Can I use dplyr to split a data frame into two data frames based on the values of a column?

Yes, you can use dplyr to split a data frame into two data frames based on the values of a column. You can use the group_by() and split() functions. For example, to split the df data frame into two data frames, one for males and one for females, you would use the following code:

df %>%

group_by(gender) %>%
split()

 This will create two data frames, df_males, and df_females, where df_males contains all of the rows in the df data frame where the gender column is equal to "male," and df_females contains all of the rows in the df data frame where the gender column is equal to "female".

Can I use dplyr to nest two data frames?

Yes, you can use dplyr to nest two data frames. To do this, you can use the nest() function. For example, to nest the df_males and df_females data frames, you would use the following code:

df_nest = list(males = df_males, females = df_females) 

This will create a nested data frame called df_nest, where the males' and females' columns contain the df_males and df_females data frames, respectively.

Can I use dplyr to perform data manipulation operations on a data frame without using base R functions?

Yes, you can use dplyr to perform data manipulation operations on a data frame without using base R functions. In fact, dplyr is designed to make data manipulation easier and more intuitive than base R functions.

For example, to filter the df data frame to only include rows where the age column is greater than 18 and the gender column is equal to "male", you can use the following dplyr code:

df %>%

filter(age > 18 & gender == "male") 

This is much easier to read and understand than using the following base R code:

df[df$age > 18 & df$gender == "male", ] 

Why should I use dplyr for data manipulation?

There are several reasons why you should use dplyr for data manipulation:

  • Dplyr is more intuitive and easier to read than base R functions.
  • Dplyr provides a consistent set of functions for performing common data manipulation operations.
  • Dplyr is highly efficient and can manipulate large datasets quickly and easily.

If you are new to R or data manipulation, I recommend using dplyr. It will make your life much easier!


Do you need help with a data analysis project? Let me assist you! With a PhD and ten years of experience, I specialize in solving data analysis challenges using R and other advanced tools. Reach out to me for personalized solutions tailored to your needs.

About the Author

Ph.D. Scholar | Certified Data Analyst | Blogger | Completed 5000+ data projects | Passionate about unravelling insights through data.

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