Given some data. How to plot the data in the same 2D plot but using two x-axes instead of only one?
- You want to have on top axis and one bottom axis.
- You want to be able to customize the ticks and labels of both the top and bottom axis.
Solution: Matplotlib Axis.twiny()
To plot two x-axes at the top and the bottom of a given plot, apply the following five steps:
- Define the
- Create a figure object with
- Configure the first x-axis using
fig.add_subplot(111)and plot the data using
ax1.plot(X, Y). You can customize the labels and ticks of the axis object with its
- Configure the second x-axis using
ax1.twiny()that creates a copy of the first x-axis that shares the same y-axis. Customize the labels and ticks of the second axis object with its
- Plot and show everything using
import matplotlib.pyplot as plt # 1. Define data X = [0, 1, 2, 3] Y = [x**2 for x in X] # 2. Define figure fig = plt.figure() # 3. Configure first x-axis and plot ax1 = fig.add_subplot(111) ax1.plot(X, Y) ax1.set_xlabel("Original x-axis") ax1.set_xticks((0, 1, 2, 3)) # 4. Configure second x-axis ax2 = ax1.twiny() ax2.set_xticks((0.5, 1.5, 2.5)) ax2.set_xlabel("Modified x-axis") # 5. Make the plot visible plt.show()
The output is the following beauty with two axis instead of only one:
For example, if you want to change the number of ticks and the label of the second x axis, you can do so here:
# ... # 4. Configure second x-axis ax2 = ax1.twiny() ax2.set_xticks([0.2 * x for x in range(20)]) ax2.set_xlabel("FINXTER LEARN PYTHON!") # 5. Make the plot visible plt.show()
Now, have a look at the output—what has changed?
Yes, Python also plots the yellow sun around the second axis. I swear. Not. 😉
While working as a researcher in distributed systems, Dr. Christian Mayer found his love for teaching computer science students.
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