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R ggplot2 Boxplot

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The R ggplot2 boxplot is useful to graphically visualizing the numeric data, group by specific data. In this article we will show you, How to Create a ggplot boxplot, Format the colors, changing labels, drawing horizontal boxplots, and plot multiple boxplots using R ggplot2 with example. For this, we will use two data sets provided by the R, and they are: ChickWeight and diamonds data set

TIP: ggplot2 package is not installed by default. Please refer Install R Packages article to understand the steps involved in installing a package.

Create R ggplot2 Boxplot

In this example we will show you, How to create a Boxplot using the ggplot2 package, and for this we are going to use the ChickWeight data set, provided by the R Studio.

NOTE: If your requirement is to import data from external files then please refer R Read CSV article to understand the steps involved in csv file import

R CODE

# Create a R ggplot boxplot

# Importing the ggplot2 library
library(ggplot2)

# Create a Boxplot
ggplot(ChickWeight, aes(x = Diet, y = weight)) + 
  geom_boxplot()

OUTPUT

R ggplot2 Boxplot 1

Change Colors of a Boxplot in R

In this example we will show you, How to change the Boxplot box colors using fill argument

  • fill: Please specify the color you want to use for your Boxplot. Type colors() in your console to get the list of colors available in R programming

R CODE

# Add Color to R ggplot boxplot

# Importing the ggplot2 library
library(ggplot2)

# Create a Boxplot
ggplot(diamonds, aes(x = cut, y = price)) + 
  geom_boxplot(fill = "midnightblue")

OUTPUT

R ggplot2 Boxplot 2

Change Colors of a Boxplot in R example 2

In this example we will show you, How to change the Boxplot box colors using column data. Here, we are using the cut column data to differenciate the colors

R CODE

# Add Color to R ggplot boxplot

# Importing the ggplot2 library
library(ggplot2)

# Create a Boxplot
ggplot(diamonds, aes(x = cut, y = price, fill = cut)) + 
  geom_boxplot(outlier.colour="black", outlier.shape=16, outlier.size=2)

OUTPUT

R ggplot2 Boxplot 3

Change Outliners of a R ggplot2 Boxplot

In this example we will show you, How to change the boxplot outliners colors using following arguments

  • outlier.color: Please specify the color you want to use for your outliner. Type colors() in your console to get the list of colors available in R programming
  • outlier.shape: Please specify the shape you want to use for outliner.
  • outlier.size: Specify the size of the outliner.

R CODE

# Change Outliers in a R ggplot boxplot

# Importing the ggplot2 library
library(ggplot2)

# Create a Boxplot
ggplot(diamonds, aes(x = cut, y = price, fill = cut)) + 
  geom_boxplot(outlier.color = "seagreen", outlier.shape = 8, outlier.size = 2)

OUTPUT

R ggplot2 Boxplot 4

Add Mean to a R ggplot2 Boxplot

In this example we will show you, How to add Mean value to boxplot using stat_summary argument

R CODE

# Adding Mean to a R ggplot boxplot

# Importing the ggplot2 library
library(ggplot2)

# Create a Boxplot
ggplot(diamonds, aes(x = cut, y = price, fill = cut)) + 
  geom_boxplot() +
  stat_summary(fun.y = "mean", geom = "point", shape = 8, size = 2, color = "white")

OUTPUT

R ggplot2 Boxplot 5

Alter Legend position of a R ggplot2 Boxplot

By default ggplot will position the legend at the right side of a Boxplot. In this example we will show you, How to change the legend position from right to top. Note, You can use legend.position = “none” to completely remove the legend.

R CODE

# Alter lengend Position in a a R ggplot boxplot

# Importing the ggplot2 library
library(ggplot2)

# Create a Boxplot
ggplot(diamonds, aes(x = cut, y = price, fill = cut)) + 
  geom_boxplot() +
  theme(legend.position = "top")

OUTPUT

R ggplot2 Boxplot 6

Notch argument in R Boxplot

In this example we will show you, How to draw a line on each side of the boxes using notch argument

  • notch: It is a Boolean argument. If it is TRUE, a notch is drawn on each side of the box.

TIP: If the notches of 2 plots are overlapped then, we can say that the medians of them are same otherwise, they are different.

R CODE

# Notch argument in R ggplot boxplot

# Importing the ggplot2 library
library(ggplot2)

# Create a Boxplot
ggplot(ChickWeight, aes(x = Diet, y = weight)) + 
  geom_boxplot(fill = "chocolate", notch = TRUE)

OUTPUT

R ggplot2 Boxplot 7

Horizontal ggplot Boxplot in R

In this example we will show you, How to change the default vertical boxplot into horizontal box plot using coord_flip() function

R CODE

# Create Horizontal R ggplot boxplot

# Importing the ggplot2 library
library(ggplot2)

# Create a Boxplot
ggplot(ChickWeight, aes(x = Diet, y = weight)) + 
  geom_boxplot() +
  coord_flip()

OUTPUT

R ggplot2 Boxplot 8

Multiple ggplot Boxplot in R

In this example we will show you, How to group multiple boxplots

R CODE

# Multiple R ggplot boxplot

# Importing the ggplot2 library
library(ggplot2)

# Create a Boxplot Importing
ggplot(diamonds, aes(x = cut, y = price, fill = clarity)) + 
  geom_boxplot()

OUTPUT

R ggplot2 Boxplot 9

How to use Facets in R ggplot2 Boxplot

This example we will show you, How to draw multiple boxplots, by dividing the data based on column value. Here, we are using the clarity column data to divide the boxplots

R CODE

# Use Facet in R ggplot boxplot

# Importing the ggplot2 library
library(ggplot2)

# Create a Boxplot Importing
ggplot(diamonds, aes(x = cut, y = price, fill = clarity)) + 
  geom_boxplot() +
  facet_wrap(~ clarity)

OUTPUT

R ggplot2 Boxplot 10

How to use Facets in R ggplot2 Boxplot example 2

By default facet_wrap() will assign the same y-axis to all the boxplot but, you can change it (giving independent axis) to each and every boxplot by adding one more attribute called scale.

R CODE

# Use Facet in R ggplot boxplot

# Importing the ggplot2 library
library(ggplot2)

# Create a Boxplot Importing
ggplot(diamonds, aes(x = cut, y = price, fill = clarity)) + 
  geom_boxplot() +
  facet_wrap(~ clarity, scale = "free")

OUTPUT

R ggplot2 Boxplot 11

Assigning names to R ggplot Boxplot

In this example we will show you, How to assign names to ggplot boxplot, X-Axis, and Y-Axis using labs function

R CODE

# Add Labels to R ggplot boxplot

# Importing the ggplot2 library
library(ggplot2)

# Create a Boxplot Importing
ggplot(diamonds, aes(x = cut, y = price, fill = cut)) + 
  geom_boxplot() +
  labs(title="GGPLOT BOXPLOT", x="Price in Dollars", y="Cut")

OUTPUT

R ggplot2 Boxplot 12

Change R ggplot2 boxplot Theme

In this example we will show you, How to change the default theme of a ggplot boxplot

  • theme_dark(): We are using this function to change the boxplot default theme to dark. Type theme_ then R Studio intelligence will show you the list of available options. For example, theme_grey()

R CODE

# Change themeof a R ggplot boxplot

# Importing the ggplot2 library
library(ggplot2)

# Create a Boxplot Importing
ggplot(diamonds, aes(x = cut, y = price, fill = cut)) + 
  geom_boxplot() +
  labs(title="GGPLOT BOXPLOT", x="Price in Dollars", y="Cut") +
  theme_dark()

OUTPUT

R ggplot2 Boxplot 13

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