The “geom_line” Function in R

• Package: ggplot2

• Purpose: To add a layer of lines to a plot, connecting points in the order of the data frame.

• General Class: Plot Layer

• Required Argument(s):

• None

• Notable Optional Arguments:

• mapping: Aesthetic mappings created by the aes function.

• data: The data frame providing the data for the plot.

• position: Position adjustment method for overlapping lines.

• color, size: Aesthetics for line characteristics.

• linetype: Type of line to draw.

• Example:

• # Example usage
  library(ggplot2)
  
  # Create a data frame with more observations
  my_data <- data.frame(
  Category = rep(c("A", "B", "C", "D"), each = 2),
  Value = c(10, 15, 20, 25, 15, 20, 25, 30)
  )
  
  # Create a ggplot object with lines
  my_plot <- ggplot(data = my_data, aes(x = Category, y = Value)) +
  geom_line(color = "red", size = 1.5, linetype = "dashed") +
  labs(title = "Line Plot of Values by Category", x = "Category", y = "Value")
  
  # Print the plot with lines
  print(my_plot)

• In this example, the geom_line function from the ggplot2 package is used to create a line plot, and optional arguments customize the appearance of the lines.