How to add title to subplots in Matplotlib?

If you want to make it shorter, you could write :

import matplotlib.pyplot as plt
for i in range(4):
    plt.subplot(2,2,i+1).set_title(f'Subplot n°{i+1}')
plt.show()

It makes it maybe less clear but you don't need more lines or variables

ax.title.set_text('My Plot Title') seems to work too.

fig = plt.figure()
ax1 = fig.add_subplot(221)
ax2 = fig.add_subplot(222)
ax3 = fig.add_subplot(223)
ax4 = fig.add_subplot(224)
ax1.title.set_text('First Plot')
ax2.title.set_text('Second Plot')
ax3.title.set_text('Third Plot')
ax4.title.set_text('Fourth Plot')
plt.show()

ax.set_title() should set the titles for separate subplots:

import matplotlib.pyplot as plt

if __name__ == "__main__":
    data = [1, 2, 3, 4, 5]

    fig = plt.figure()
    fig.suptitle("Title for whole figure", fontsize=16)
    ax = plt.subplot("211")
    ax.set_title("Title for first plot")
    ax.plot(data)

    ax = plt.subplot("212")
    ax.set_title("Title for second plot")
    ax.plot(data)

    plt.show()

Can you check if this code works for you? Maybe something overwrites them later?

A shorthand answer assuming import matplotlib.pyplot as plt:

plt.gca().set_title('title')

as in:

plt.subplot(221)
plt.gca().set_title('title')
plt.subplot(222)
etc...

Then there is no need for superfluous variables.