How to remove stemline(s) from a matplotlib stem plot?

Question

Here is an example script to create a stem plot in matplotlib.

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

import matplotlib.pyplot as plt
import numpy as np

# returns 10 evenly spaced samples from 0.1 to 2*PI
x = np.linspace(0.1, 2 * np.pi, 10)

fig, ax = plt.subplots( figsize=(4.,3.), constrained_layout=True)
markerline, stemline, baseline = ax.stem(x, np.cos(x), '-.', use_line_collection=True)
markerline1, stemline1, baseline1 = ax.stem(x, np.cos(x*5), '-', use_line_collection=True)

plt.setp(baseline, color='black', linewidth=2)
plt.setp(baseline1, color='black', linewidth=2)
plt.setp( stemline, color="green" )
plt.setp( stemline1, color="red" )

plt.show()

Q1. After creating these plots, I would like to remove for example markerline1 , stemline1 , baseline1 . How do I remove them?

Q2. If I would like to remove the entire stem plot from ax without affecting other settings of ax , how do I do so? I found that ax.clear() removes everything from ax .

According to matplotlib,

UserWarning: In Matplotlib 3.3 individual lines on a stem plot will be added as a LineCollection instead of individual lines.

Also, LineCollection appears to have an attribute called segment that contains the x,y info of all the stem lines.

Q3. How do I get the LineCollection object from ax or fig ? I am exploring if amending the LineCollection object is a method to answer my first question.

Answer 1

You can use obj.remove() to remove objects from a plot after they have been plot, ie markerline1.remove() , etc.

More details here

This can be extended to Q2 by looping over all the objects you have on your plot if you named them before.