Themes and theme customization in R Programming - Mini Project: Build & Apply

Themes and Theme Customization in R

📖 Scenario: You are creating a simple bar chart to show sales data for different products. You want to make the chart look nicer by changing the theme colors and text styles.

🎯 Goal: Build a bar chart using ggplot2 with a customized theme that changes the background color, text size, and axis titles.

📋 What You'll Learn

Create a data frame called sales_data with products and their sales numbers

Create a variable called base_size to set the base font size for the theme

Use ggplot() to create a bar chart with geom_bar() using sales_data

Customize the plot theme using theme() to change background color, axis title size, and text color

Print the final plot

💡 Why This Matters

🌍 Real World

Customizing themes helps make charts clearer and more attractive for presentations and reports.

💼 Career

Data analysts and scientists often need to adjust chart styles to match company branding or improve readability.

1

Create the sales data

Create a data frame called sales_data with these exact entries: Product as 'A', 'B', 'C' and Sales as 30, 45, 25.

R Programming

# Create the sales_data data frame with Product and Sales columns
# Your code here

Need a hint?

Use data.frame() with Product = c('A', 'B', 'C') and Sales = c(30, 45, 25).

2

Set the base font size

Create a variable called base_size and set it to 14 to control the font size in the theme.

R Programming

sales_data <- data.frame(Product = c('A', 'B', 'C'), Sales = c(30, 45, 25))
# Create base_size variable and set it to 14
# Your code here

Need a hint?

Just assign 14 to base_size.

3

Create the bar chart with customized theme

Use ggplot() with sales_data, map Product to x and Sales to y, add geom_bar(stat = 'identity'), and customize the theme with theme() to set panel.background to light gray, axis title text size to base_size, and axis text color to blue.

R Programming

sales_data <- data.frame(Product = c('A', 'B', 'C'), Sales = c(30, 45, 25))
base_size <- 14

# Create ggplot bar chart with customized theme
# Your code here

Need a hint?

Use theme() to customize background and text styles.

4

Display the customized plot

Print the plot stored in the variable plot to display the customized bar chart.

R Programming

library(ggplot2)
sales_data <- data.frame(Product = c('A', 'B', 'C'), Sales = c(30, 45, 25))
base_size <- 14

plot <- ggplot(sales_data, aes(x = Product, y = Sales)) +
  geom_bar(stat = 'identity') +
  theme(
    panel.background = element_rect(fill = 'lightgray'),
    axis.title = element_text(size = base_size),
    axis.text = element_text(color = 'blue')
  )

# Print the plot
# Your code here

Need a hint?

Use print(plot) to show the plot.