Why pie charts show proportions in Matplotlib - See It in Action

Why Pie Charts Show Proportions

📖 Scenario: Imagine you run a small bakery and want to understand which types of pastries sell the most. You have sales data for different pastry types and want to visualize their share of total sales.

🎯 Goal: You will create a pie chart using matplotlib to show the proportions of pastry sales. This will help you see which pastries are most popular at a glance.

📋 What You'll Learn

Create a dictionary called pastry_sales with exact pastry names and sales numbers

Create a variable called total_sales that sums all sales

Use a for loop with variables pastry and sales to calculate proportions

Use matplotlib.pyplot.pie() to create a pie chart showing proportions

Print the proportions dictionary to see the share of each pastry

💡 Why This Matters

🌍 Real World

Pie charts are used in business to quickly show how parts make up a whole, like sales shares or budget spending.

💼 Career

Data analysts and scientists use pie charts to communicate proportions clearly to stakeholders and help make decisions.

1

Create the pastry sales data

Create a dictionary called pastry_sales with these exact entries: 'Croissant': 120, 'Muffin': 80, 'Danish': 50, 'Eclair': 30

Matplotlib

# Create the pastry_sales dictionary with exact values
# Your code here

Need a hint?

Use curly braces {} to create a dictionary with pastry names as keys and sales numbers as values.

2

Calculate total sales

Create a variable called total_sales that sums all the sales values in pastry_sales using the sum() function and .values() method

Matplotlib

pastry_sales = {'Croissant': 120, 'Muffin': 80, 'Danish': 50, 'Eclair': 30}
# Create total_sales by summing pastry_sales values
# Your code here

Need a hint?

Use sum(pastry_sales.values()) to add all sales numbers.

3

Calculate proportions of each pastry

Create an empty dictionary called proportions. Use a for loop with variables pastry and sales to iterate over pastry_sales.items(). Inside the loop, calculate the proportion as sales / total_sales and store it in proportions[pastry]

Matplotlib

pastry_sales = {'Croissant': 120, 'Muffin': 80, 'Danish': 50, 'Eclair': 30}
total_sales = sum(pastry_sales.values())
# Create proportions dictionary and fill it with sales proportions
# Your code here

Need a hint?

Use a for loop to go through each pastry and calculate its share by dividing sales by total_sales.

4

Create and show the pie chart

Import matplotlib.pyplot as plt. Use plt.pie() with the sales values from pastry_sales.values() and labels from pastry_sales.keys(). Add autopct='%1.1f%%' to show percentages. Use plt.title() to add the title 'Pastry Sales Proportions'. Finally, call plt.show() to display the chart. Also, print the proportions dictionary.

Matplotlib

pastry_sales = {'Croissant': 120, 'Muffin': 80, 'Danish': 50, 'Eclair': 30}
total_sales = sum(pastry_sales.values())
proportions = {}
for pastry, sales in pastry_sales.items():
    proportions[pastry] = sales / total_sales
# Import matplotlib.pyplot as plt and create the pie chart
# Print the proportions dictionary
# Your code here

Need a hint?

Remember to import matplotlib.pyplot as plt. Use plt.pie() with sales values and labels, add autopct for percentages, then show the plot with plt.show(). Finally, print the proportions dictionary.