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R ggplot2 Violin Plot

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The R ggplot2 Violin Plot is useful to graphically visualizing the numeric data, group by specific data. In this article we will show you, How to Create a ggplot violin plot, Format its colors, drawing horizontal violin plots, and plot multiple violin plot using R ggplot2 with example. For this, we will use the diamonds data set provided by the R

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

R ggplot2 Violin Plot Syntax

The syntax to draw a violin plot in R Programming is as shown below

geom_violin(mapping = NULL, data = NULL, stat = "ydensity",
  position = "dodge", ..., draw_quantiles = NULL, trim = TRUE,
  scale = "area", na.rm = FALSE, show.legend = NA, inherit.aes = TRUE)

Create a basic R ggplot2 Violin Plot

In this example we will show you, How to create a basic violin plot using the ggplot2 package, and for this we are going to use the diamonds 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 R ggplot Violin plot

# Importing the ggplot2 library
library(ggplot2)

# Create a Violin plot
ggplot(diamonds, aes(x = cut, y = price)) + 
  geom_violin()

OUTPUT

R ggplot2 Violin Plot 1

Creating R ggplot2 Violin Plot

In our previous example, data is huge so there is no visibility of the proper violin plot. In this example we will scale the y value with log10 and create a violin plot using the scaled y.

R CODE

# Create R ggplot Violin plot

# Importing the ggplot2 library
library(ggplot2)

# Create a Violin plot
ggplot(diamonds, aes(x = cut, y = price)) + 
  geom_violin() + scale_y_log10()

OUTPUT

R ggplot2 Violin Plot 2

Change Colors of a Violin Plot in R

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

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

R CODE

# Change Colors of a R ggplot Violin plot

# Importing the ggplot2 library
library(ggplot2)

# Create a Violin plot
ggplot(diamonds, aes(x = cut, y = price)) + 
  geom_violin(fill = "seagreen") + scale_y_log10()

OUTPUT

R ggplot2 Violin Plot 3

Change Colors of a R Violin Plot using Columns

In this example we will show you, How to change the violin plot colors using column data. Here, we are using the cut column data to differentiate the colors

R CODE

# Change Colors of a R ggplot Violin plot

# Importing the ggplot2 library
library(ggplot2)

# Create a Violin plot
ggplot(diamonds, aes(x = cut, y = price, fill = cut)) + 
  geom_violin() + scale_y_log10()

OUTPUT

R ggplot2 Violin Plot 4

Trimming the R Violin Plot using Columns

In this example we will show you, How to trim, not to trim the data in violin plot using trim argument

R CODE

# Trimming R ggplot Violin plot

# Importing the ggplot2 library
library(ggplot2)

# Create a Violin plot
ggplot(diamonds, aes(x = clarity, y = price, fill = clarity)) + 
  geom_violin(trim = FALSE) + scale_y_log10())

OUTPUT

R ggplot2 Violin Plot 5

Add Mean & Median to R ggplot2 Violin Plot

In this example we will show you, How to add Mean, and Median value to violin plot using stat_summary function

R CODE

# Adding Mean & Median to R ggplot Violin plot

# Importing the ggplot2 library
library(ggplot2)

# Create a Violin plot
ggplot(diamonds, aes(x = cut, y = price, fill = cut)) + 
  geom_violin() + scale_y_log10() +
  stat_summary(fun.y = "mean", geom = "point", shape = 8, size = 3, color = "midnightblue") +
  stat_summary(fun.y = "median", geom = "point", shape = 2, size = 3, color = "red")

OUTPUT

R ggplot2 Violin Plot 6

Add Boxplot to R ggplot2 Violin Plot

In this example we will show you, How to add boxplot to R Violin Plot using geom_boxplot function. This can help us to see the Median, along with the quartile for our violin plot.

TIP: Please refer R ggplot2 Boxplot article to understand the Boxplot arguments.

R CODE

# Adding Boxplot to R ggplot Violin plot

# Importing the ggplot2 library
library(ggplot2)

# Create a Violin plot
ggplot(diamonds, aes(x = cut, y = price, fill = cut)) + 
  geom_violin() + scale_y_log10() +
  geom_boxplot(width = 0.2)

OUTPUT

R ggplot2 Violin Plot 7

Alter Legend position of a R ggplot2 Violin Plot

By default ggplot will position the legend at the right side of a violin plot. 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 legend position of a R ggplot Violin plot

# Importing the ggplot2 library
library(ggplot2)

# Create a Violin plot
ggplot(diamonds, aes(x = cut, y = price, fill = cut)) + 
  geom_violin() + scale_y_log10() +
  geom_boxplot(width = 0.2) +
  theme(legend.position = "top")

OUTPUT

R ggplot2 Violin Plot 8

Horizontal ggplot Violin Plot in R

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

R CODE

# Change X, Y Axis in a R ggplot Violin plot

# Importing the ggplot2 library
library(ggplot2)

# Create a Violin plot
ggplot(diamonds, aes(x = cut, y = price, fill = cut)) + 
  geom_violin() + scale_y_log10() +
  geom_boxplot(width = 0.2) +
  coord_flip()

OUTPUT

R ggplot2 Violin Plot 9

Multiple ggplot Violin plots in R

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

R CODE

# Multiple R ggplot Violin plot

# Importing the ggplot2 library
library(ggplot2)

# Create a Violin plot
ggplot(diamonds, aes(x = cut, y = price, fill = clarity)) + 
  geom_violin() + scale_y_log10()

OUTPUT

R ggplot2 Violin Plot 10

How to use Facets in R ggplot2 Violin plot

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

R CODE

# Multiple R ggplot Violin plot

# Importing the ggplot2 library
library(ggplot2)

# Create a Violin plot
ggplot(diamonds, aes(x = cut, y = price, fill = clarity)) + 
  geom_violin(trim= FALSE) + scale_y_log10() +
  facet_wrap(~ clarity)

OUTPUT

R ggplot2 Violin Plot 11

By default facet_wrap() will assign the same y-axis to all the violin plot but, you can change it (giving independent axis) to each and every violin plot by adding one more attribute called scale. facet_wrap(~ clarity, scale = “free”)

Assigning names to R ggplot Violin plot

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

R CODE

# Add Names to R ggplot Violin plot

# Importing the ggplot2 library
library(ggplot2)

# Create a Violin plot
ggplot(diamonds, aes(x = cut, y = price, fill = clarity)) + 
  geom_violin(trim= FALSE) + scale_y_log10() +
  facet_wrap(~ clarity) +
  labs(title="GGPLOT VIOLIN PLOT", x="Price in Dollars", y="Cut")

OUTPUT

R ggplot2 Violin Plot 12

Change R ggplot2 Violin plot Theme

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

  • theme_dark(): We will use this function to change the violin plot default theme to dark. If you type theme_ then R Studio intelligence will show you the list of available options. For example, theme_grey()

R CODE

# Change theme of a R ggplot Violin plot

# Importing the ggplot2 library
library(ggplot2)

# Create a Violin plot
ggplot(diamonds, aes(x = cut, y = price, fill = cut)) + 
  geom_violin(trim = FALSE) + scale_y_log10() +
  geom_boxplot(width = 0.2) +
  labs(title="GGPLOT VIOLIN PLOT", x="Price in Dollars", y="Cut") +
  theme_dark()

OUTPUT

R ggplot2 Violin Plot 13

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