In this article, we are going to discuss how to create y-axes of both sides of a Matplotlib plot.
Sometimes for quick data analysis, it is required to create a single graph having two data variables with different scales. For this purpose twin axes methods are used i.e. dual X or Y-axes. The matplotlib.axes.Axes.twinx() function in axes module of matplotlib library is used to create a twin Axes sharing the X-axis.
Syntax :
matplotlib.axes.Axes.twinx(self)
This method does not take any parameters, raise an error if provided. It returns the ax_twin object which indicates that a new Axes instance is created. Below examples illustrate the matplotlib.axes.Axes.twinx() function in matplotlib.axes:
Example 1:
Python3
# import librariesimport numpy as npimport matplotlib.pyplot as plt# Creating datasetx = np.arange(1.0, 100.0, 0.191)dataset_1 = np.exp(x**0.25) - np.exp(x**0.5)dataset_2 = np.sin(0.4 * np.pi * x**0.5) + np.cos(0.8 * np.pi * x**0.25)# Creating plot with dataset_1fig, ax1 = plt.subplots()color = 'tab:red'ax1.set_xlabel('X-axis')ax1.set_ylabel('Y1-axis', color = color)ax1.plot(x, dataset_1, color = color)ax1.tick_params(axis ='y', labelcolor = color)# Adding Twin Axes to plot using dataset_2ax2 = ax1.twinx()color = 'tab:green'ax2.set_ylabel('Y2-axis', color = color)ax2.plot(x, dataset_2, color = color)ax2.tick_params(axis ='y', labelcolor = color)# Adding titleplt.title('Use different y-axes on the left and right of a Matplotlib plot', fontweight ="bold")# Show plotplt.show() |
Output:
Example 2:
Python3
# import librariesimport numpy as npimport matplotlib.pyplot as pltfrom matplotlib import rcrc('mathtext', default='regular')# Creating datasetx = np.arange(10)dataset_1 = np.random.random(10)*30dataset_2 = np.random.random(10)*60dataset_3 = np.random.random(10)*100# Creating figurefig = plt.figure()# Plotting dataset_2ax = fig.add_subplot(111)ax.plot(x, dataset_2, '-', label='dataset_2')ax.plot(x, dataset_3, '-', label='dataset_3')# Creating Twin axes for dataset_1ax2 = ax.twinx()ax2.plot(x, dataset_1, '-r', label='dataset_1')# Adding titleplt.title('Use different y-axes on the left and right of a Matplotlib plot', fontweight="bold")# Adding legendax.legend(loc=0)ax2.legend(loc=0)# adding gridax.grid()# Adding labelsax.set_xlabel("X-axis")ax.set_ylabel(r"Y1-axis")ax2.set_ylabel(r"Y2-axis")# Setting Y limitsax2.set_ylim(0, 35)ax.set_ylim(-20, 100)# Show plotplt.show() |
Output:
