How to Add Title to Subplots in Matplotlib

  1. Set_title() Method to Add Title to Subplot in Matplotlib
  2. title.set_text() Method to Set Title of Subplots in Matplotlib
  3. plt.gca().set_title() / plt.gca.title.set_text() to Set Title to Subplots in Matplotlib

We use set_title(label) and title.set_text(label) methods to add titles to subplots in Matplotlib.

Set_title() Method to Add Title to Subplot in Matplotlib

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

import numpy as np
import matplotlib.pyplot as plt

x = np.linspace(-3,3,100)
y1 = np.sin(x)
y2 = np.cos(x)
y3 = 1/(1+np.exp(-x))
y4 = np.exp(x)

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

ax[0, 0].plot(x, y1)
ax[0, 1].plot(x, y2)
ax[1, 0].plot(x, y3)
ax[1, 1].plot(x,y4)

ax[0, 0].set_title("Sine function")
ax[0, 1].set_title("Cosine function")
ax[1, 0].set_title("Sigmoid function")
ax[1, 1].set_title("Exponential function")

fig.tight_layout()
plt.show()

Output:

set_title to add title to subplot in Matplotlib

If we want to loop over some subplots and show them one at a time along with titles, we can use the following shorter code:

import numpy as np
import matplotlib.pyplot as plt

x=np.linspace(-3,3,100)
y=[0,0,0,0]
y[0]=np.sin(x)
y[1]=np.cos(x)
y[2]=1/(1+np.exp(-x))
y[3]=np.exp(x)

figure, ax = plt.subplots(2, 2)
i=0
for a in range(len(ax)): 
    for b in range(len(ax[a])):
        ax[a, b].plot(x, y[i])
        subplot_title=("Subplot"+str(i))
        ax[a,b].set_title(subplot_title)
        i=i+1

figure.tight_layout()
plt.show()

Output:

set_title to add title to subplot in Matplotlib - loop method

title.set_text() Method to Set Title of Subplots in Matplotlib

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

import numpy as np
import matplotlib.pyplot as plt

x=np.linspace(-3,3,100)
y1=np.sin(x)
y2=np.cos(x)
y3=1/(1+np.exp(-x))
y4=np.exp(x)

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

ax[0, 0].plot(x, y1)
ax[0, 1].plot(x, y2)
ax[1, 0].plot(x, y3)
ax[1, 1].plot(x,y4)

ax[0, 0].title.set_text("Sine function")
ax[0, 1].title.set_text("Cosine function")
ax[1, 0].title.set_text("Sigmoid function")
ax[1, 1].title.set_text("Exponential function")

fig.tight_layout()
plt.show()
        

Output:

title.set_text Method to add title to subplot in Matplotlib

plt.gca().set_title() / plt.gca.title.set_text() to Set Title to Subplots in Matplotlib

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() or title.set_text() method to set title to the subplots in Matplotlib.

import matplotlib.pyplot as plt
plt.subplots(2, 2) 
x = [1, 2, 3]
y = [2, 4, 6]


for i in range(4):
    plt.subplot(2, 2, i+1)
    plt.plot(x, y)
    plt.gca().set_title('Title-' + str(i))

plt.show()

plt.tight_layout()

or,

import matplotlib.pyplot as plt
plt.subplots(2, 2) 
x = [1, 2, 3]
y = [2, 4, 6]


for i in range(4):
    plt.subplot(2, 2, i+1)
    plt.plot(x, y)
    plt.gca().title.set_text('Title-' + str(i))

plt.show()

plt.tight_layout()

Related Article - Matplotlib Subplot

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