How to set Transparency for Bars of Bar Plot in Matplotlib?

Matplotlib PyPlot – Set Transparency for Bar Plot

To set transparency for bars in a Bar Plot using Matplotlib PyPlot API, call matplotlib.pyplot.bar() function, and pass required alpha value to alpha parameter of bar() function.

The definition of matplotlib.pyplot.bar() function with alpha parameter is

bar(x, height, alpha=None)

Of course, there are other named parameters, but for simplicity, only alpha parameter is given along with required x and height.

where

Parameter	Description
alpha	The transparency of bars in the bar plot. The parameter takes a scalar or None.

Example

In the following program, we will draw a bar plot with bars 50% transparency, which translates to an alpha of 0.5.

example.py

import matplotlib.pyplot as plt

#data
x = [1, 2, 3, 4, 5]
h = [10, 8, 12, 4, 7]

#bar plot
plt.bar(x, height=h, alpha=0.5)

plt.show()

Output

Now, let us try with an alpha of 1.0, which is also the default value using which the bar plot is drawn.

example.py

import matplotlib.pyplot as plt

#data
x = [1, 2, 3, 4, 5]
h = [10, 8, 12, 4, 7]

#bar plot
plt.bar(x, height=h, alpha=1.0)

plt.show()

Output

Conclusion

In this Matplotlib Tutorial, we learned how to set line width for bars in bar plot using Matplotlib PyPlot API.