Step 1: Create a Basic Bar Chart

Start by creating a basic bar chart representing the population distribution for one gender. We’ll use the geom_bar function to do this.

# Create a basic bar chart for one gender
basic_plot <-  ggplot(
    data, 
    aes(
        x = Age, 
        fill = Gender, 
        y = ifelse(
            test = Gender == "Male", 
            yes = -Population, 
            no = Population
            )
        )
    ) + 
geom_bar(stat = "identity") 

In this code:

• We filter the data to include only one gender (Male) using subset.
• We use aes to specify the aesthetic mappings. We map Age to the x-axis, -Population to the y-axis (note the negative sign to flip the bars), and Age to the fill color.
• geom_bar is used to create the bar chart, and stat = "identity" ensures that the heights of the bars are determined by the Population variable.
• Finally, coord_flip() is applied to flip the chart horizontally, making it look like a pyramid.

Step 2: Combine Both Genders

To create a population pyramid, we need to combine both male and female data. We’ll create two separate plots for each gender and then combine them using the + operator.

# Create population pyramids for both genders and combine them
population_pyramid <- basic_plot +
  scale_y_continuous(
    labels = abs, 
    limits = max(data$Population) * c(-1,1)
  ) + 
  coord_flip() + 
  theme_minimal() +
  labs(
    x = "Age", 
    y = "Population", 
    fill = "Age", 
    title = "Population Pyramid"
  )

In this step:

• scale_y_continuous(labels = abs, limits = max(data$Population) * c(-1,1)):
• This part adjusts the y-axis (vertical axis) of the plot.
• labels = abs means that the labels on the y-axis will show the absolute values (positive numbers) rather than negative values.
• limits = max(data$Population) * c(-1,1) sets the limits of the y-axis. It ensures that the y-axis extends from the maximum population value (positive) to the minimum (negative) value, creating a symmetrical pyramid shape.
• coord_flip(): This function flips the coordinate system of the plot. By default, the x-axis (horizontal) represents age, and the y-axis (vertical) represents population. coord_flip() swaps them so that the x-axis represents population and the y-axis represents age, creating the pyramid effect.
• theme_minimal(): This sets the overall visual theme of the plot to a minimalistic style. It adjusts the background, gridlines, and other visual elements to a simple and clean appearance.
• labs(x = “Age”, y = “Population”, fill = “Age”, title = “Population Pyramid”): This part labels various elements of the plot:
  • x = “Age” labels the x-axis as “Age.”
  • y = “Population” labels the y-axis as “Population.”
  • fill = “Age” specifies that the “Age” variable will be used to fill the bars in the plot.
  • title = “Population Pyramid” sets the title of the plot as “Population Pyramid.”

Step 3: Customize Your Plot

Feel free to customize your plot further by adding labels, adjusting colors, or modifying other aesthetics to match your preferences. The ggplot2 library provides extensive customization options.

Step 4: Visualize Your Population Pyramid

To visualize your population pyramid, simply print the population_pyramid object:

population_pyramid

This will display the population pyramid plot in your R graphics window.