Remove Legend in ggplot2 (3 Example Codes) | Delete One or All Legends

 

This tutorial shows how to remove legends in plots of the R ggplot2 package. The article is structured as follows:

Let’s dive right in!

 

Create Example Data

Let’s first create an example data frame, which we can use in the examples later on:

set.seed(2468)                                                   # Set seed for reproducibility
data <- data.frame(x = c(rnorm(100, 1, 0.5), rnorm(20, 3, 0.3)), # Create x variable
                   y = c(rnorm(100, 1, 0.1), rnorm(20, 3, 1)),   # Ceate y variable
                   col12 = c(rep("col1", 100), rep("col2", 20)), # Create first color variable
                   col3 = "col3")                                # Create second color variable
head(data)                                                       # Print first 6 rows of data
#           x        y col12 col3
# 1 0.9530222 1.091612  col1 col3
# 2 0.8404038 1.082346  col1 col3
# 3 0.6221827 1.067994  col1 col3
# 4 1.2294909 1.006801  col1 col3
# 5 1.3508563 1.051379  col1 col3
# 6 0.1878442 1.015002  col1 col3

Our example data contains four columns, the first column contains the x-values; the second column contains the y-values; the third column contains the colors for the dots of our plot; and the fourth column contains the filling color for a regression line that we will draw to our graphic.

So let’s see how this data looks in ggplot2 by default. First, we need to install and load the ggplot2 package in R…

install.packages("ggplot2")                                      # Install ggplot2 package
library("ggplot2")                                               # Load ggplot2 package

…and then we can draw a scatterplot with corresponding regression line as follows:

my_ggplot <- ggplot(data, aes(x, y, group = col12)) +            # ggplot2 with 2 legends 
  geom_point(aes(x, y, col = col12)) + 
  geom_smooth(method = "lm", formula = y ~ x,
              aes(group = col3, fill = col3))
my_ggplot                                                        # Print plot with 2 legends

 

R ggplot2 with all Legends

Figure 1: ggplot2 of Example Data with Two Legends.

 

As you can see in Figure 1, by default the previous R code prints two legends on the side of the dotplot.

In the following examples, I’ll show you how to delete one of these legends or how to switch off all legends. So let’s move on to the examples…

 

Example 1: Remove All Legends in ggplot2

If we want to remove all legends of our graph, we can use the following R syntax:

my_ggplot + theme(legend.position = "none")                      # Remove all legends from plot

 

R ggplot2 with no Legends

Figure 2: ggplot2 of Example Data without Legends.

 

We simply had to specify legend.position = “none” within the theme options to get rid of both legends.

But what if we want to keep one of the legends and remove the other? That’s what I’m going to show you next.

 

Example 2a: Hide One Specific Legend in ggplot2 with guides()

This example is called 2a, because there is an alternative solution that I will show you in the next example. However, in this example, we will remove one specific legend with the guides command.

The guides command can be used to specify an aesthetic, for which no legend should be shown.

We can use the guides command to delete the legend for the fill aesthetic…

my_ggplot + guides(fill = FALSE)                                 # Remove legend for aes fill

 

R ggplot2 with first Legend

Figure 3: ggplot2 of Example Data with First Legend.

 

…or we can use guides to turn off the legend for the col aesthetic:

my_ggplot + guides(col = FALSE)                                  # Remove legend for aes col

 

R ggplot2 with second Legend

Figure 4: ggplot2 of Example Data with Second Legend.

 

Of cause, this kind of code could also be applied to other aesthetics as well as to other kinds of plots (histogram, barchart, QQplot etc.).

At this point, you have learned basically all things you need to know in order to remove legends in R ggplots. However, I want to show you another alternative, which can also be quite handy sometimes. So keep on reading…

 

Example 2b: Hide One Specific Legend in ggplot2 with show.legend

Another solution for removing legends in ggplots is the show.legend option. By default, this option is specified to be TRUE. We can modify this default value manually as follows to turn off the first legend…

my_ggplot_2b.1 <- ggplot(data, aes(x, y, group = col12)) +       # ggplot2 with 1 legend
  geom_point(aes(x, y, col = col12)) +
  geom_smooth(method = "lm", formula = y ~ x,
              aes(group = col3, fill = col3),
              show.legend = FALSE)                               # Remove second legend
my_ggplot_2b.1                                                   # Print plot with 1 legend

…and as follows to hide the second legend…

my_ggplot_2b.2 <- ggplot(data, aes(x, y, group = col12)) +       # ggplot2 with 1 legend
  geom_point(aes(x, y, col = col12),
             show.legend = FALSE) +                              # Remove first legend
  geom_smooth(method = "lm", formula = y ~ x,
              aes(group = col3, fill = col3))
my_ggplot_2b.2                                                   # Print plot with 1 legend

The output of these R codes is the same as in Example 2a.

 

Further Resources for ggplot2

The ggplot2 environment is very complex and might sometimes be difficult to understand. For that reason I can recommend to learn ggplot from scratch once, instead of struggling with it again and again. If you want to improve your ggplot2 skills, I can recommend the following YouTube video of the Data Science Dojo channel:

 

 

Furthermore, you may also have a look at the other R programming tutorials of this website. Here you can find some interesting reads:

In this tutorial I explained how to remove legends in ggplot2. The tutorial should include everything you need to know in order to delete a legend properly. However, in case you have any further questions or recommendations for improvements of the tutorial, you can let me know in the comments!

 



 

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