ggplot2 Themes Exercises in R: 30 Practice Problems
Thirty practice problems on ggplot2 themes: built-ins, axis customization, legend, gridlines, plot title, custom theme functions. Hidden solutions.
RRun this once before any exercise
library(ggplot2)
Section 1. Built-in themes (6 problems)
Exercise 1.1: theme_minimal
Difficulty: Beginner.
Show solution
RInteractive R
ggplot(mtcars, aes(wt, mpg)) + geom_point() + theme_minimal()
Exercise 1.2: theme_bw
Difficulty: Beginner.
Show solution
RInteractive R
ggplot(mtcars, aes(wt, mpg)) + geom_point() + theme_bw()
Exercise 1.3: theme_classic
Difficulty: Beginner.
Show solution
RInteractive R
ggplot(mtcars, aes(wt, mpg)) + geom_point() + theme_classic()
Exercise 1.4: theme_void
Difficulty: Beginner.
Show solution
RInteractive R
ggplot(mtcars, aes(wt, mpg)) + geom_point() + theme_void()
Exercise 1.5: theme_dark
Difficulty: Beginner.
Show solution
RInteractive R
ggplot(mtcars, aes(wt, mpg)) + geom_point() + theme_dark()
Exercise 1.6: Set global default
Difficulty: Intermediate.
Show solution
RInteractive R
old <- theme_set(theme_minimal())
ggplot(mtcars, aes(wt, mpg)) + geom_point()
theme_set(old)
Section 2. Title and labels (5 problems)
Exercise 2.1: Bold title
Difficulty: Beginner.
Show solution
RInteractive R
ggplot(mtcars, aes(wt, mpg)) + geom_point() +
labs(title = "Demo") +
theme(plot.title = element_text(face = "bold"))
Exercise 2.2: Center the title
Difficulty: Beginner.
Show solution
RInteractive R
ggplot(mtcars, aes(wt, mpg)) + geom_point() +
labs(title = "Demo") +
theme(plot.title = element_text(hjust = 0.5))
Exercise 2.3: Larger axis labels
Difficulty: Intermediate.
Show solution
RInteractive R
ggplot(mtcars, aes(wt, mpg)) + geom_point() +
theme(axis.title = element_text(size = 14))
Exercise 2.4: Italic subtitle
Difficulty: Intermediate.
Show solution
RInteractive R
ggplot(mtcars, aes(wt, mpg)) + geom_point() +
labs(subtitle = "demo") +
theme(plot.subtitle = element_text(face = "italic"))
Exercise 2.5: Right-aligned caption
Difficulty: Intermediate.
Show solution
RInteractive R
ggplot(mtcars, aes(wt, mpg)) + geom_point() +
labs(caption = "Source: mtcars") +
theme(plot.caption = element_text(hjust = 1))
Section 3. Axis ticks and text (6 problems)
Exercise 3.1: Rotate x labels
Difficulty: Intermediate.
Show solution
RInteractive R
ggplot(diamonds, aes(clarity)) + geom_bar() +
theme(axis.text.x = element_text(angle = 45, hjust = 1))
Exercise 3.2: Hide x axis text
Difficulty: Intermediate.
Show solution
RInteractive R
ggplot(mtcars, aes(wt, mpg)) + geom_point() +
theme(axis.text.x = element_blank())
Exercise 3.3: Larger axis text
Difficulty: Intermediate.
Show solution
RInteractive R
ggplot(mtcars, aes(wt, mpg)) + geom_point() +
theme(axis.text = element_text(size = 12))
Exercise 3.4: Bold y axis title
Difficulty: Intermediate.
Show solution
RInteractive R
ggplot(mtcars, aes(wt, mpg)) + geom_point() +
theme(axis.title.y = element_text(face = "bold"))
Exercise 3.5: Remove tick marks
Difficulty: Advanced.
Show solution
RInteractive R
ggplot(mtcars, aes(wt, mpg)) + geom_point() +
theme(axis.ticks = element_blank())
Exercise 3.6: Custom font family
Difficulty: Advanced.
Show solution
RInteractive R
ggplot(mtcars, aes(wt, mpg)) + geom_point() +
theme(text = element_text(family = "serif"))
Section 4. Legend (6 problems)
Exercise 4.1: Bottom legend
Difficulty: Beginner.
Show solution
RInteractive R
ggplot(iris, aes(Sepal.Length, Petal.Length, color = Species)) + geom_point() +
theme(legend.position = "bottom")
Exercise 4.2: No legend
Difficulty: Beginner.
Show solution
RInteractive R
ggplot(iris, aes(Sepal.Length, Petal.Length, color = Species)) + geom_point() +
theme(legend.position = "none")
Exercise 4.3: Inside-plot legend
Difficulty: Intermediate.
Show solution
RInteractive R
ggplot(iris, aes(Sepal.Length, Petal.Length, color = Species)) + geom_point() +
theme(legend.position = c(0.2, 0.8))
Exercise 4.4: Legend title
Difficulty: Intermediate.
Show solution
RInteractive R
ggplot(iris, aes(Sepal.Length, Petal.Length, color = Species)) + geom_point() +
labs(color = "Iris species")
Exercise 4.5: Larger legend text
Difficulty: Intermediate.
Show solution
RInteractive R
ggplot(iris, aes(Sepal.Length, Petal.Length, color = Species)) + geom_point() +
theme(legend.text = element_text(size = 12))
Exercise 4.6: Hide one legend with guides
Difficulty: Advanced.
Show solution
RInteractive R
ggplot(mtcars, aes(wt, mpg, color = factor(cyl), size = hp)) + geom_point() +
guides(size = "none")
Section 5. Gridlines and panel (4 problems)
Exercise 5.1: Remove minor grid
Difficulty: Intermediate.
Show solution
RInteractive R
ggplot(mtcars, aes(wt, mpg)) + geom_point() +
theme(panel.grid.minor = element_blank())
Exercise 5.2: Remove all gridlines
Difficulty: Intermediate.
Show solution
RInteractive R
ggplot(mtcars, aes(wt, mpg)) + geom_point() +
theme(panel.grid = element_blank())
Exercise 5.3: Custom panel background
Difficulty: Advanced.
Show solution
RInteractive R
ggplot(mtcars, aes(wt, mpg)) + geom_point() +
theme(panel.background = element_rect(fill = "lightyellow"))
Exercise 5.4: Add a panel border
Difficulty: Advanced.
Show solution
RInteractive R
ggplot(mtcars, aes(wt, mpg)) + geom_point() +
theme(panel.border = element_rect(color = "black", fill = NA, size = 1))
Section 6. Custom theme function (3 problems)
Exercise 6.1: Reusable function
Difficulty: Advanced.
Show solution
RInteractive R
my_theme <- function() {
theme_minimal() +
theme(plot.title = element_text(face = "bold", hjust = 0.5),
legend.position = "bottom")
}
ggplot(mtcars, aes(wt, mpg)) + geom_point() + labs(title = "demo") + my_theme()
Exercise 6.2: Theme function with args
Difficulty: Advanced.
Show solution
RInteractive R
my_theme <- function(base_size = 12) theme_minimal(base_size = base_size)
ggplot(mtcars, aes(wt, mpg)) + geom_point() + my_theme(14)
Exercise 6.3: Replace default
Difficulty: Advanced.
Show solution
RInteractive R
theme_replace(panel.grid.minor = element_blank())
ggplot(mtcars, aes(wt, mpg)) + geom_point()
What to do next
- ggplot2-Exercises (shipped), broader practice.
- ggplot2-Color-Scales-Exercises (coming), palettes and color theory.