Infinite lines

axvline and axhline draw infinite vertical / horizontal lines, at given x / y positions. They are usually used to mark special data values, e.g. in this example the center and limit values of the sigmoid function.

axline draws infinite straight lines in arbitrary directions.

import numpy as np
import matplotlib.pyplot as plt

t = np.linspace(-10, 10, 100)
sig = 1 / (1 + np.exp(-t))

plt.axhline(y=0, color="black", linestyle="--")
plt.axhline(y=0.5, color="black", linestyle=":")
plt.axhline(y=1.0, color="black", linestyle="--")
plt.axvline(color="grey")
plt.axline((0, 0.5), slope=0.25, color="black", linestyle=(0, (5, 5)))
plt.plot(t, sig, linewidth=2, label=r"$\sigma(t) = \frac{1}{1 + e^{-t}}$")
plt.xlim(-10, 10)
plt.xlabel("t")
plt.legend(fontsize=14)
plt.show()
axline

References

The use of the following functions, methods, classes and modules is shown in this example:

Out:

<function Axes.axline at 0x7f9f9240aaf0>

Keywords: matplotlib code example, codex, python plot, pyplot Gallery generated by Sphinx-Gallery