How to Add Title to Subplots in Matplotlib?

In this article, we will see how to add a title to subplots in Matplotlib? Let’s discuss some concepts :

• Matplotlib : Matplotlib is an amazing visualization library in Python for 2D plots of arrays. Matplotlib is a multi-platform data visualization library built on NumPy arrays and designed to work with the broader SciPy stack. It was introduced by John Hunter in the year 2002.
• Subplots : The subplots() function in pyplot module of matplotlib library is used to create a figure and a set of subplots. Subplots are required when we want to show two or more plots in same figure.
• Title of a plot : The title() method in matplotlib module is used to specify title of the visualization depicted and displays the title using various attributes.

Steps Needed

• Import Libraries
• Create/ Load data
• Make subplot
• Plot subplot
• Set title to subplots.

Example 1: (Using set_title() method)

We use matplotlib.axes._axes.Axes.set_title(label) method to set title (string label) for the current subplot Axes.

Python3

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

# create data
x=np.array([1, 2, 3, 4, 5])

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

# set data with subplots and plot
ax[0, 0].plot(x, x)
ax[0, 1].plot(x, x*2)
ax[1, 0].plot(x, x*x)
ax[1, 1].plot(x, x*x*x)

# set the title to subplots
ax[0, 0].set_title("Linear")
ax[0, 1].set_title("Double")
ax[1, 0].set_title("Square")
ax[1, 1].set_title("Cube")

# set spacing
fig.tight_layout()
plt.show()

Output:

Example 2: (Using title.set_text() method)

We can also add title to subplots in Matplotlib using title.set_text() method, in similar way to set_title() method.

Python3

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

# create data
x=np.array([1, 2, 3, 4, 5])

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

# set data with subplots and plot
ax[0, 0].plot(x, x)
ax[0, 1].plot(x, x*2)
ax[1, 0].plot(x, x*x)
ax[1, 1].plot(x, x*x*x)

# set the title to subplots
ax[0, 0].title.set_text("Linear")
ax[0, 1].title.set_text("Double")
ax[1, 0].title.set_text("Square")
ax[1, 1].title.set_text("Cube")

# set spacing
fig.tight_layout()
plt.show()

Output:

Example 3: (Using plt.gca().set_title() method)

If you use Matlab-like style in the interactive plotting, then you could use plt.gca() to get the reference of the current axes of the subplot and combine set_title() method to set title to the subplots in Matplotlib.

Python3

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

# create data
x=np.array([1, 2, 3, 4, 5])

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

# set data with subplots and plot
title = ["Linear", "Double", "Square", "Cube"]
y = [x, x*2, x*x, x*x*x]

for i in range(4):

    # subplots
    plt.subplot(2, 2, i+1)

    # plotting (x,y)
    plt.plot(x, y[i])

    # set the title to subplots
    plt.gca().set_title(title[i])

# set spacing
fig.tight_layout()
plt.show()

Output :

Example 4: (Using plt.gca().title.set_text() method)

If you use Matlab-like style in the interactive plotting, then you could use plt.gca() to get the reference of the current axes of the subplot and combine title.set_text() method to set title to the subplots in Matplotlib.

Python3

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

# create data
x=np.array([1, 2, 3, 4, 5])

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

# set data with subplots and plot
title = ["Linear","Double","Square","Cube"]
y = [x, x*2, x*x, x*x*x]

for i in range(4):

    # subplots
    plt.subplot(2, 2, i+1)

    # plotting (x,y)
    plt.plot(x, y[i])

    # set the title to subplots
    plt.gca().title.set_text(title[i])

# set spacing
fig.tight_layout()
plt.show()

Output :