The R ggplot2 Violin Plot is useful to graphically visualizing the numeric data group by specific data. Let us see how to Create a ggplot2 violin plot in R, Format its colors. And drawing horizontal violin plots, plot multiple violin plots using R ggplot2 with example. For this R ggplot Violin Plot demo, we use the diamonds data set provided by the R.
R ggplot2 Violin Plot Syntax
The syntax to draw a violin plot in R Programming is
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 show how to create a basic violin plot using the ggplot2 package. For this example, we are going to use the diamonds data set provided by the R Studio.
TIP: ggplot2 package not installed by default. Please refer Install R Packages article to understand installing the package.
# Create R ggplot Violin plot # Importing the ggplot2 library library(ggplot2) # Create a Violin plot ggplot(diamonds, aes(x = cut, y = price)) + geom_violin()
Creating R ggplot2 Violin Plot
In our previous R ggplot violin plot example, data is huge, so there is no visibility of the proper violin plot. In this example, we scale y value with log10 and create a violin plot using the scaled y.
NOTE: If you require to import data from external files, then please refer to R Read CSV to understand importing the CSV file in R Programming.
# 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()
Change Colors of a ggplot Violin Plot in R
In this example, we show 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
# 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()
Change Colors of an R ggplot2 Violin Plot using Columns
This R ggplot violin plot example, we show how to change the violin plot colors using column data. Here, we are using the cut column data to differentiate the colors.
# 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()
Trimming the R Violin Plot using Columns
Let us see how to trim, not to trim the data in the violin plot using trim argument
# 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())
Add Mean & Median to R ggplot2 Violin Plot
Let us see how to add Mean and Median value to the violin plot using stat_summary function.
# 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")
Add Boxplot to R ggplot2 Violin Plot
In this example, we show how to add a boxplot to R Violin Plot using geom_boxplot function. It 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.
# 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)
Alter Legend position of a R ggplot2 Violin Plot
By default, ggplot position the legend at the right side of a violin plot.
In this example, we change the legend position of the R ggplot violin plot from right to the top. Note, You can use a legend.position = “none” to altogether remove the legend.
# 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")
Horizontal ggplot Violin Plot in R
In this R ggplot violin plot example, we change the default vertical violin plot into a horizontal violin plot using coord_flip() function
# 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()
Multiple ggplot Violin plots in R
In this R ggplot violin plot example, we show how to group multiple violin plots
# 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()
How to use Facets in R ggplot2 Violin plot
This R ggplot violin plot example, we 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
# 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)
By default, facet_wrap() assigns the same y-axis to all the violin plot. But, you can change it (giving independent axis) to each violin plot by adding one more attribute called scale. facet_wrap(~ clarity, scale = “free”).
Assigning names to ggplot2 Violin plot
In this example, we show you how to assign names to R ggplot violin plot, X-Axis, and Y-Axis using labs function
# 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")
Change ggplot2 Violin plot Theme
In this example, we show how to change the default theme of an R ggplot violin plot.
- theme_dark(): We use this function to change the violin plot default theme to dark. If you type theme_, then R Studio intelligence shows the list of available options. For example, theme_grey().
# 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()
