program 10

Program 10

Develop an R program to draw a density curve representing the probability density function of a continuous variable, with separate curves for each group, using ggplot2.

# Load required package
library(ggplot2)

# Define a function to draw density plots
plot_density_by_group <- function(data, continuous_var, group_var, fill_colors = NULL) {
  
  # Check if the columns exist in the dataset
  if (!(continuous_var %in% names(data)) || !(group_var %in% names(data))) {
    stop("Invalid column names: Make sure both variables exist in the dataset.")
  }

  # Create the ggplot object
  p <- ggplot(data, aes_string(x = continuous_var, color = group_var, fill = group_var)) +
    geom_density(alpha = 0.4) +  # semi-transparent fill
    labs(
      title = paste("Density Plot of", continuous_var, "by", group_var),
      x = continuous_var,
      y = "Density"
    ) +
    theme_minimal() +
    theme(plot.title = element_text(hjust = 0.5))  # center the title

  # If custom fill colors are provided
  if (!is.null(fill_colors)) {
    p <- p +
      scale_fill_manual(values = fill_colors) +
      scale_color_manual(values = fill_colors)
  }

  # Return the plot
  return(p)
}

# Example usage with iris dataset
# Plot Sepal.Length by Species
plot_density_by_group(iris, "Sepal.Length", "Species")

Warning: `aes_string()` was deprecated in ggplot2 3.0.0.
ℹ Please use tidy evaluation idioms with `aes()`.
ℹ See also `vignette("ggplot2-in-packages")` for more information.