The “theme_set” Function in R

• Package: ggplot2

• Purpose: To set the default theme for ggplot2 plots for the current session.

• General Class: Data Visualization

• Required Argument(s):

• theme: The theme object to set as the default.

• Notable Optional Arguments:

• No notable optional arguments for this function.

• Example (with Explanation):

• # Load necessary packages
  library(ggplot2)
  
  # Plot with the system default theme
  ggplot(mtcars, aes(x = mpg, y = disp)) +
  geom_point() +
  labs(title = "Scatter Plot with Default Theme")
  
  # Create a custom dark mode theme
  Dark_Mode <- theme_dark() +
  theme(plot.background = element_rect(fill = "black"),
  panel.background = element_rect(fill = "black"),
  axis.text = element_text(color = "white"),
  axis.title = element_text(color = "white"),
  plot.title = element_text(color = "white"))
  
  # Set the custom theme as the default theme
  theme_set(Dark_Mode)
  
  # Plot with the new dark default theme, added color = "white"
  ggplot(mtcars, aes(x = mpg, y = disp)) +
  geom_point(color = "white") +
  labs(title = "Scatter Plot with Dark Theme")
  
  # Reset the default theme back to minimal
  theme_set(theme_minimal())
  
  # Plot with the default theme
  ggplot(mtcars, aes(x = mpg, y = disp)) +
  geom_point() +
  labs(title = "Scatter Plot with Default Theme")

• In this example, the theme_set function is used to set a custom theme as the default for the current session. The custom theme is applied to a new scatter plot, and then the theme is reset to the default for the session. This function allows you to easily change the default theme for all subsequent plots in a session.