Search code examples
pythonmatplotlibplotaxes

Adding colored boxes to axes in Python's matplotlib

Community,

Say I have created a scatter plot with Python's matplotlib:

plt.scatter(x, y)

Let's say this is the data: enter image description here

Now, is there a way to add colored boxes on the axis (between given x-values, e.g.,: add a green box from x=-0.2 to x=0, add a ...) like this: enter image description here

Including the text labels (at the mid-range I guess).

I am not even sure how to get started on this one to be honest (besides making the scatter plot).

Question Can anyone at least direct me to a feature of matplotlib that does this (or any other Python package)?

Your help is much appreciated.

Solution

  • You probably want to go with matplotlib's text() function. Maybe something like this,

    import numpy as np
import matplotlib.pyplot as plt

x = np.linspace(0, 1, 100)
y = np.sin(2*np.pi * x)

fig = plt.figure()
ax = fig.add_subplot(111)
ax.plot(x, y, 'o')
ax.set_xlim(-0.2, 1.2)
ax.set_ylim(-1.5, 1.5)

x_ticks = ax.get_xticks()
y_ticks = ax.get_yticks()
# use len(x_ticks)-1 number of colors
colors = ['b', 'g', 'r', 'c', 'm', 'y', 'orange']
for i, x_tick in enumerate(x_ticks[:-1]):
    ax.text(x_tick+0.03, y_ticks[0]-0.165, "text %i"%i,
            bbox={'fc':colors[i], 'pad':10})

    This code returns this image. You can adjust the padding and x,y position as necessary to achieve the exact look you're going for.