Pie Charts in Matplotlib
Pie charts are used to display the proportions of parts of a whole. Each slice of the pie represents a category, with its size corresponding to its proportion.
Creating Pie Charts
The pie() function in Matplotlib is used to create pie charts.
Example: Basic Pie Chart
import matplotlib.pyplot as plt
# Data
labels = ['Python', 'Java', 'C++', 'JavaScript']
sizes = [215, 130, 245, 210]
# Create pie chart
plt.pie(sizes, labels=labels, autopct='%1.1f%%', startangle=90)
# Add title
plt.title("Programming Language Popularity")
# Display the plot
plt.show()Customizing Pie Charts
Matplotlib provides several parameters to customize pie charts:
| Parameter | Description | Example Value |
|---|---|---|
labels | Names of the categories | ['A', 'B', 'C'] |
autopct | Display format for percentage values | '%1.1f%%' |
startangle | Starting angle of the chart | 90 |
colors | Colors for each slice | ['red', 'blue'] |
explode | Offset for slices (proportional values) | [0.1, 0, 0] |
Example: Customized Pie Chart
# Data
labels = ['Apples', 'Bananas', 'Cherries', 'Dates']
sizes = [20, 30, 25, 25]
colors = ['gold', 'yellowgreen', 'lightcoral', 'lightskyblue']
explode = [0.1, 0, 0, 0] # Explode the first slice
# Create customized pie chart
plt.pie(sizes, labels=labels, autopct='%1.1f%%', startangle=140, colors=colors, explode=explode)
# Add title
plt.title("Fruit Distribution")
# Display the plot
plt.show()Adding Legends and Annotations
Legends and annotations enhance the readability of pie charts.
Example: Pie Chart with Legend
# Data
labels = ['Rent', 'Groceries', 'Utilities', 'Entertainment']
sizes = [500, 300, 100, 100]
# Create pie chart
plt.pie(sizes, labels=labels, autopct='%1.1f%%', startangle=90)
plt.title("Monthly Expenses")
# Add legend
plt.legend(labels, title="Categories", loc="best")
# Display the plot
plt.show()Practical Examples
Example 1: Survey Results
# Data
labels = ['Satisfied', 'Neutral', 'Dissatisfied']
sizes = [60, 25, 15]
colors = ['green', 'yellow', 'red']
# Create pie chart
plt.pie(sizes, labels=labels, autopct='%1.1f%%', startangle=90, colors=colors)
# Add title
plt.title("Customer Satisfaction Survey")
# Display the plot
plt.show()Example 2: Market Share
# Data
labels = ['Company A', 'Company B', 'Company C', 'Company D']
sizes = [40, 30, 20, 10]
# Create pie chart
plt.pie(sizes, labels=labels, autopct='%1.1f%%', startangle=90, colors=['blue', 'orange', 'green', 'red'])
# Add title
plt.title("Market Share Distribution")
# Display the plot
plt.show()Try It Yourself
Problem 1: Create a Pie Chart
Create a pie chart to represent the percentage distribution of your daily activities: sleeping, studying, exercising, and leisure.
Show Code
# Data
labels = ['Sleeping', 'Studying', 'Exercising', 'Leisure']
sizes = [8, 6, 2, 8]
# Create pie chart
plt.pie(sizes, labels=labels, autopct='%1.1f%%', startangle=90)
# Add title
plt.title("Daily Activity Distribution")
# Display the plot
plt.show()Problem 2: Favorite Hobbies
Create a pie chart showing the distribution of survey responses for favorite hobbies.
Show Code
# Data
labels = ['Reading', 'Traveling', 'Cooking', 'Gaming']
sizes = [25, 30, 20, 25]
# Create pie chart
plt.pie(sizes, labels=labels, autopct='%1.1f%%', startangle=140, colors=['cyan', 'magenta', 'yellow', 'lime'])
# Add title
plt.title("Favorite Hobbies")
# Display the plot
plt.show()Pie charts are excellent for showing proportions. Experiment with various options to create engaging visualizations that effectively communicate your data.
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Output:
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