How to Set a Single Main Title for All the Subplots in Matplotlib?

A title in Matplotlib library describes the main subject of plotting the graphs. Setting a title for just one plot is easy using the title() method. By using this function only the individual title plots can be set but not a single title for all subplots. Hence, to set a single main title for all subplots, suptitle() method is used.

Syntax: suptitle(self, t, **kwargs)

Parameters: This method accept the following parameters that are discussed below:

• t : This parameter is the title text.
• x: This parameter is the x location of the text in figure coordinates.
• y: This parameter is the y location of the text in figure coordinates.
• horizontalalignment, ha : This parameter is the horizontal alignment of the text relative to (x, y).
• verticalalignment, va : This parameter is the vertical alignment of the text relative to (x, y).
• fontsize, size : This parameter is the font size of the text.
• fontweight, weight : This parameter is the font weight of the text.

Returns: This method returns the Text instance of the title.

Setting a Single Title for All the Subplots

Example 1:

In this example, we will import the required library and create a 2*2 plot. We are creating random data by using random.randint to plot our graph and then setting a single title for all the subplots.

# importing packages
import matplotlib.pyplot as plt
import numpy as np

# making subplots objects
fig, ax = plt.subplots(2, 2)

# draw graph
ax[0][0].plot(np.random.randint(0, 5, 5), np.random.randint(0, 5, 5))
ax[0][1].plot(np.random.randint(0, 5, 5), np.random.randint(0, 5, 5))
ax[1][0].plot(np.random.randint(0, 5, 5), np.random.randint(0, 5, 5))
ax[1][1].plot(np.random.randint(0, 5, 5), np.random.randint(0, 5, 5))


fig.suptitle(' Set a Single Main Title for All the Subplots ', fontsize=30)

plt.show()

Output:

Example 2:

Here, we are creating data to plot our graph and using a marker.

import matplotlib.pyplot as plt
import numpy as np

fig, (ax1, ax2) = plt.subplots(1, 2, figsize=(12, 5))

x1 = [1, 2, 3, 4, 5, 6]
y1 = [45, 34, 30, 45, 50, 38]
y2 = [36, 28, 30, 40, 38, 48]

labels = ["student 1", "student 2"]

# Add title to subplot
fig.suptitle(' Student marks in different subjects ', fontsize=30)

# Creating the sub-plots.
l1 = ax1.plot(x1, y1, 'o-', color='g')
l2 = ax2.plot(x1, y2, 'o-')

fig.legend([l1, l2], labels=labels,
           loc="upper right")
plt.subplots_adjust(right=0.9)

plt.show()

Output: