Axis Label in Matplotlib

In Matplotlib, axis labels are important components of a plot as they help in understanding the data being displayed. In this article, we will explore how to add and customize axis labels in Matplotlib plots.

Adding Axis Labels

To add axis labels to a plot in Matplotlib, we can use the xlabel() and ylabel() functions. These functions take a string as an argument which specifies the label for the x-axis and y-axis respectively.

import matplotlib.pyplot as plt

x = [1, 2, 3, 4, 5]
y = [10, 20, 15, 25, 30]

plt.plot(x, y)
plt.xlabel('X-axis label')
plt.ylabel('Y-axis label')
plt.show()

Output:

Customizing Axis Labels

We can customize the appearance of axis labels by changing properties such as font size, font style, color, rotation, and alignment.

import matplotlib.pyplot as plt

x = [1, 2, 3, 4, 5]
y = [10, 20, 15, 25, 30]

plt.plot(x, y)

plt.xlabel('X-axis label', fontsize=12, fontstyle='italic', color='red', rotation=45, ha='right')
plt.ylabel('Y-axis label', fontsize=12, fontstyle='italic', color='blue', rotation=45, va='top')

Adding Units to Axis Labels

We can add units to axis labels by including them within the label string.

import matplotlib.pyplot as plt

x = [1, 2, 3, 4, 5]
y = [10, 20, 15, 25, 30]

plt.plot(x, y)

plt.xlabel('Time (s)')
plt.ylabel('Temperature (°C)')

Formatting Axis Labels

We can format axis labels using string formatting to display them in a specific way.

import matplotlib.pyplot as plt

x = [1, 2, 3, 4, 5]
y = [10, 20, 15, 25, 30]

plt.plot(x, y)

plt.xlabel('Value: {:.2f}')
plt.ylabel('Count: {:,}')

Adding Math Symbols to Axis Labels

Matplotlib supports LaTeX syntax for adding math symbols to axis labels.

import matplotlib.pyplot as plt

x = [1, 2, 3, 4, 5]
y = [10, 20, 15, 25, 30]

plt.plot(x, y)

plt.xlabel(r'$\theta$ (radians)')
plt.ylabel(r'$\lambda$ (meters)')

Adding Multiple Lines to Axis Labels

We can add multiple lines to axis labels by using newline characters \n.

import matplotlib.pyplot as plt

x = [1, 2, 3, 4, 5]
y = [10, 20, 15, 25, 30]

plt.plot(x, y)

plt.xlabel('Line 1\nLine 2')
plt.ylabel('Line 1\nLine 2')

Adding Axis Labels to Subplots

When working with subplots in Matplotlib, we can add axis labels to each subplot individually.

import matplotlib.pyplot as plt

x = [1, 2, 3, 4, 5]
y = [10, 20, 15, 25, 30]

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

axs[0, 0].plot(x, y)
axs[0, 0].set_xlabel('Subplot 1 X-axis')
axs[0, 0].set_ylabel('Subplot 1 Y-axis')

axs[0, 1].scatter(x, y)
axs[0, 1].set_xlabel('Subplot 2 X-axis')
axs[0, 1].set_ylabel('Subplot 2 Y-axis')

plt.show()

Output:

Removing Axis Labels

If you want to remove axis labels from your plot, you can use the set_visible() function with False as an argument.

import matplotlib.pyplot as plt

x = [1, 2, 3, 4, 5]
y = [10, 20, 15, 25, 30]

plt.xlabel('X-axis label')
plt.ylabel('Y-axis label')

plt.gca().axes.xaxis.set_label_visible(False)
plt.gca().axes.yaxis.set_label_visible(False)
plt.show()