matplotlib / pandas：在时间序列图中沿着绘制线放置线标签

Question

I am plotting time series data comparing system characteristics from multiple nodes. I want to label the line from a particular node explicitly along its line. So far I have succeeded in putting separate line style for the particular node, which gives it distinctive line and distinctive style marker in the legend box.

I am trying to find a way to put distinctive label along the line, possibly text curving along the line. Any way to achieve that?

Answer 1

Text curving along the line isn't easy to do with matplotlib, but annotate will allow you to easily label the line with text and an arrow.

Eg

import matplotlib.pyplot as plt
import numpy as np

# Generate some data
x = np.linspace(0, 20, 200)
y = np.cos(x) + 0.5 * np.sin(3 * x)

fig, ax = plt.subplots()
ax.plot(x, y)

ax.annotate(r'$y = cos(x) + \frac{sin(3x)}{2}$', xy=(x[70], y[70]), 
            xytext=(20, 10), textcoords='offset points', va='center',
            arrowprops=dict(arrowstyle='->'))
plt.show()