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You can easily adjust the thickness of lines in Matplotlib plots by using the **linewidth** argument function, which uses the following syntax:

**matplotlib.pyplot.plot(x, y, linewidth=1.5)**

By default, the line width is 1.5 but you can adjust this to any value greater than 0.

This tutorial provides several examples of how to use this function in practice.

**Example 1: Adjust the Thickness of One Line**

The following code shows how to create a simple line chart and set the line width to 3:

import matplotlib.pyplot as plt import numpy as np #define x and y values x = np.linspace(0, 10, 100) y1 = np.sin(x)*np.exp(-x/3) #create line plot with line width set to 3 plt.plot(x, y1, linewidth=3) #display plot plt.show()

**Example 2: ****Adjust the Thickness of Multiple Lines**

The following code shows how to adjust the thickness of multiple lines at once:

import matplotlib.pyplot as plt import numpy as np #define x and y values x = np.linspace(0, 10, 100) y1 = np.sin(x)*np.exp(-x/3) y2 = np.cos(x)*np.exp(-x/5) #create line plot with multiple lines plt.plot(x, y1, linewidth=3) plt.plot(x, y2, linewidth=1) #display plot plt.show()

**Example 3: Adjust Line Thickness in Legends**

The following code shows how to create multiple lines with different thicknesses and create a legend that displays the the thickness of each line accordingly:

import matplotlib.pyplot as plt import numpy as np #define x and y values x = np.linspace(0, 10, 100) y1 = np.sin(x)*np.exp(-x/3) y2 = np.cos(x)*np.exp(-x/5) #create line plot with multiple lines plt.plot(x, y1, linewidth=3, label='y1') plt.plot(x, y2, linewidth=1, label='y2') #add legend plt.legend() #display plot plt.show()

**Additional Resources**

How to Fill in Areas Between Lines in Matplotlib

How to Remove Ticks from Matplotlib Plots

How to Place the Legend Outside of a Matplotlib Plot