Matplotlib provides several ways to add a single overarching title to a figure containing multiple subplots. This enhances readability and provides crucial context to your visualizations. This article explores two primary methods, highlighting their similarities and subtle differences.
Table of Contents
Using pyplot.suptitle()
The pyplot.suptitle() function offers a concise way to add a main title. It’s part of the matplotlib.pyplot module (typically imported as plt). This method is straightforward and widely used.
import matplotlib.pyplot as plt
# Sample data
x = [1, 2, 3, 4, 5]
y1 = [2, 4, 1, 3, 5]
y2 = [1, 3, 5, 2, 4]
# Create subplots
fig, axes = plt.subplots(2, 1)
# Plot data
axes[0].plot(x, y1)
axes[0].set_title('Subplot 1')
axes[1].plot(x, y2)
axes[1].set_title('Subplot 2')
# Add main title
plt.suptitle('Main Figure Title', fontsize=14)
# Adjust layout (crucial to prevent overlap)
plt.tight_layout(rect=[0, 0.03, 1, 0.95])
plt.show()
The plt.tight_layout() function is essential. It automatically adjusts subplot parameters to prevent title overlap. The rect parameter fine-tunes the layout; you might need to adjust its values based on your title length and the number of subplots.
Using figure.suptitle()
Alternatively, the figure.suptitle() method, accessed via the figure object itself, provides equivalent functionality. This approach aligns with an object-oriented programming style.
import matplotlib.pyplot as plt
# Sample data (same as above)
x = [1, 2, 3, 4, 5]
y1 = [2, 4, 1, 3, 5]
y2 = [1, 3, 5, 2, 4]
# Create subplots
fig, axes = plt.subplots(2, 1)
# Plot data
axes[0].plot(x, y1)
axes[0].set_title('Subplot 1')
axes[1].plot(x, y2)
axes[1].set_title('Subplot 2')
# Add main title using the figure object
fig.suptitle('Main Figure Title (Object-Oriented)', fontsize=14)
# Adjust layout
plt.tight_layout(rect=[0, 0.03, 1, 0.95])
plt.show()
This code mirrors the previous example, demonstrating the interchangeable nature of these two methods.
Choosing the Right Method
Both methods achieve identical results. The choice often boils down to personal preference or coding style. pyplot.suptitle() is more concise, while figure.suptitle() aligns better with a strictly object-oriented approach. Consistency within your project is key. Remember to always employ plt.tight_layout() or manually adjust subplot parameters to ensure a clean and readable figure.