How to make thicker stem lines in matplolib

Question

I want to make thicker stem lines in python when using plt.stem.

Here is my code

import matplotlib.pyplot as plt
import numpy as np

N = 20

n = np.arange(0, 2*N, 1)

x = np.exp(-n/N)*np.exp(1j * 2*np.pi/N*n)

plt.stem(n,x.real) 

plt.show()

I changed plt.stem(n,x.real,linewidth=10), but nothing changed. Is there no function to set the linewidth in plt.stem?

Answer 1

This can also be modified using plt.setp() as is shown in the matplotlib documentation example. The plt.setp() method allows you to set the properties of an artist object after it has been created.

import matplotlib.pyplot as plt
import numpy as np

x = np.linspace(0.1, 2*np.pi, 10)
markerline, stemlines, baseline = plt.stem(x, np.cos(x), '-.')
plt.setp(stemlines, 'linewidth', 4)

plt.show()

Answer 2

The documentation of plt.stem shows that the function returns all the line objects created by the plot. You can use that to manually make the lines thicker after plotting:

import matplotlib.pyplot as plt
import numpy as np

N = 20
n = np.arange(0, 2*N, 1)
x = np.exp(-n/N)*np.exp(1j * 2*np.pi/N*n)

markers,stems,base = plt.stem(n,x.real) 
for stem in stems:
    stem.set_linewidth(10)
plt.show()