Matplotlib Pie Chart

We can use the pie() method from pyplot to create a pie chart.

The syntax for the pie() method is as follows:

matplotlib.pyplot.pie(x, explode=None, labels=None, colors=None, autopct=None, pctdistance=0.6, shadow=False, labeldistance=1.1, startangle=0, radius=1, counterclock=True, wedgeprops=None, textprops=None, center=(0, 0), frame=False, rotatelabels=False, *, normalize=None, data=None)[source]

Parameter Descriptions:

x: Array of floats, representing the area of each sector.

explode: Array, indicating the separation between sectors, default is 0.

labels: List, labels for each sector, default is None.

colors: Array, colors for each sector, default is None.

autopct: Format for displaying percentages inside the pie chart, %d%% for integer percentage, %0.1f for one decimal place, %0.1f%% for one decimal place percentage, %0.2f%% for two decimal place percentage.

labeldistance: The drawing position of the label marker, relative to the radius, default is 1.1, if <1 it is drawn inside the pie chart.

pctdistance: Similar to labeldistance, specifies the scale for the position of autopct, default is 0.6.

shadow: Boolean, True or False, sets the shadow for the pie chart, default is False, no shadow.

radius: Sets the radius of the pie chart, default is 1.

startangle: The starting angle for drawing the pie chart, default is counterclockwise from the positive x-axis, if set to 90, it starts from the positive y-axis.

counterclock: Boolean, sets the direction of the pointer, default is True, counterclockwise, False is clockwise.

wedgeprops: Dictionary type, default is None. Dictionary parameters passed to the wedge object to draw a pie chart. For example: wedgeprops={'linewidth': 5} sets the wedge line width to 5.

textprops: Dictionary type, default is None. Dictionary parameters passed to the text object, used to set the format of labels and percentage text.

center: List of floats, default is (0, 0). Used to set the center position of the chart.

frame: Boolean, default is False. If True, draws an axis frame with the table.

rotatelabels: Boolean, default is False. If True, rotates each label to the specified angle.

Here is a simple example using pie() to create a bar chart:

Example

import matplotlib.pyplot as plt
import numpy as np

y = np.array([35, 25, 25, 15])

plt.pie(y)
plt.show()

The result is as follows:

To set labels and colors for each sector of the pie chart:

Example

import matplotlib.pyplot as plt
import numpy as np

y = np.array([35, 25, 25, 15])

plt.pie(y,
        labels=['A', 'B', 'C', 'D'],  # Set pie chart labels
        colors=["#d5695d", "#5d8ca8", "#65a479", "#a564c9"],  # Set pie chart colors
       )
plt.title("tutorialpro Pie Test")  # Set title
plt.show()

The result is as follows:

To highlight the second sector and format the percentage output:

Example

import matplotlib.pyplot as plt
import numpy as np

y = np.array([35, 25, 25, 15])

plt.pie(y,
        labels=['A', 'B', 'C', 'D'],  # Set pie chart labels
        colors=["#d5695d", "#5d8ca8", "#65a479", "#a564c9"],  # Set pie chart colors
        explode=(0, 0.2, 0, 0),  # Highlight the second sector, the larger the value, the farther from the center
        autopct='%.2f%%',  # Format the percentage output
       )
plt.title("tutorialpro Pie Test")
plt.show()

Note: By default, the drawing of the first sector starts from the x-axis and moves counterclockwise: