Pie charts

Demo of plotting a pie chart.

This example illustrates various parameters of pie.

Label slices

Plot a pie chart of animals and label the slices. To add labels, pass a list of labels to the wedge_labels parameter.

import matplotlib.pyplot as plt

labels = 'Frogs', 'Hogs', 'Dogs', 'Logs'
sizes = [12, 24, 36, 8]

fig, ax = plt.subplots()
ax.pie(sizes, wedge_labels=labels)

Each slice of the pie chart is a patches.Wedge object; therefore in addition to the customizations shown here, each wedge can be customized using the wedgeprops argument, as demonstrated in Nested pie charts.

Set label positions

If you want the labels outside the pie, set a wedge_label_distance greater than 1. This is the distance from the center of the pie as a fraction of its radius.

fig, ax = plt.subplots()
ax.pie(sizes, wedge_labels=labels, wedge_label_distance=1.1)

Auto-label slices

Pass a format string to wedge_labels to label slices with their values...

fig, ax = plt.subplots()
ax.pie(sizes, wedge_labels='{absval:.1f}')

...or with their percentages...

fig, ax = plt.subplots()
ax.pie(sizes, wedge_labels='{frac:.1%}')

...or both.

fig, ax = plt.subplots()
ax.pie(sizes, wedge_labels='{absval:d}\n{frac:.1%}')

For more control over labels, or to add multiple sets, see Labeling pie charts.

Color slices

Pass a list of colors to colors to set the color of each slice.

fig, ax = plt.subplots()
ax.pie(sizes, colors=['olivedrab', 'rosybrown', 'gray', 'saddlebrown'])

Hatch slices

Pass a list of hatch patterns to hatch to set the pattern of each slice.

fig, ax = plt.subplots()
ax.pie(sizes, hatch=['**O', 'oO', 'O.O', '.||.'])

Explode, shade, and rotate slices

In addition to the basic pie chart, this demo shows a few optional features:

• offsetting a slice using explode

• add a drop-shadow using shadow

• custom start angle using startangle

This example orders the slices, separates (explodes) them, and rotates them.

explode = (0, 0.2, 0, 0)  # only "explode" the 2nd slice (i.e. 'Hogs')

fig, ax = plt.subplots()
ax.pie(sizes, explode=explode, wedge_labels='{frac:.1%}', shadow=True, startangle=90)
plt.show()

The default startangle is 0, which would start the first slice ("Frogs") on the positive x-axis. This example sets startangle = 90 such that all the slices are rotated counter-clockwise by 90 degrees, and the frog slice starts on the positive y-axis.

Grow or shrink pie

By changing the radius parameter, and often the text size for better visual appearance, the pie chart can be scaled.

fig, ax = plt.subplots()

ax.pie(sizes, wedge_labels='{frac:.1%}', textprops={'size': 'small'}, radius=0.5)
plt.show()

Modify shadow

The shadow parameter may optionally take a dictionary with arguments to the Shadow patch. This can be used to modify the default shadow.

fig, ax = plt.subplots()
ax.pie(sizes, explode=explode, shadow={'ox': -0.04, 'edgecolor': 'none', 'shade': 0.9},
       startangle=90)
plt.show()

References

The use of the following functions, methods, classes and modules is shown in this example:

• matplotlib.axes.Axes.pie / matplotlib.pyplot.pie

Tags: plot-type: pie level: beginner