Boxplot Demo#

Example boxplot code

import numpy as np
import matplotlib.pyplot as plt

# Fixing random state for reproducibility
np.random.seed(19680801)

# fake up some data
spread = np.random.rand(50) * 100
center = np.ones(25) * 50
flier_high = np.random.rand(10) * 100 + 100
flier_low = np.random.rand(10) * -100
data = np.concatenate((spread, center, flier_high, flier_low))
Basic Plot

Out:

{'whiskers': [<matplotlib.lines.Line2D object at 0x7f82600c9850>, <matplotlib.lines.Line2D object at 0x7f82600c9a00>], 'caps': [<matplotlib.lines.Line2D object at 0x7f82600c9610>, <matplotlib.lines.Line2D object at 0x7f82600c92e0>], 'boxes': [<matplotlib.lines.Line2D object at 0x7f825ff90d90>], 'medians': [<matplotlib.lines.Line2D object at 0x7f825dc1e0a0>], 'fliers': [<matplotlib.lines.Line2D object at 0x7f825dc1e520>], 'means': []}
fig2, ax2 = plt.subplots()
ax2.set_title('Notched boxes')
ax2.boxplot(data, notch=True)
Notched boxes

Out:

{'whiskers': [<matplotlib.lines.Line2D object at 0x7f825d557670>, <matplotlib.lines.Line2D object at 0x7f825d557a90>], 'caps': [<matplotlib.lines.Line2D object at 0x7f825d5578e0>, <matplotlib.lines.Line2D object at 0x7f825d5575e0>], 'boxes': [<matplotlib.lines.Line2D object at 0x7f825b435a90>], 'medians': [<matplotlib.lines.Line2D object at 0x7f825d557490>], 'fliers': [<matplotlib.lines.Line2D object at 0x7f825d557070>], 'means': []}
green_diamond = dict(markerfacecolor='g', marker='D')
fig3, ax3 = plt.subplots()
ax3.set_title('Changed Outlier Symbols')
ax3.boxplot(data, flierprops=green_diamond)
Changed Outlier Symbols

Out:

{'whiskers': [<matplotlib.lines.Line2D object at 0x7f825dad4b80>, <matplotlib.lines.Line2D object at 0x7f825dad43d0>], 'caps': [<matplotlib.lines.Line2D object at 0x7f825dad4f40>, <matplotlib.lines.Line2D object at 0x7f825dad4940>], 'boxes': [<matplotlib.lines.Line2D object at 0x7f825fd55d00>], 'medians': [<matplotlib.lines.Line2D object at 0x7f825dad4f70>], 'fliers': [<matplotlib.lines.Line2D object at 0x7f8228dd5b50>], 'means': []}
fig4, ax4 = plt.subplots()
ax4.set_title('Hide Outlier Points')
ax4.boxplot(data, showfliers=False)
Hide Outlier Points

Out:

{'whiskers': [<matplotlib.lines.Line2D object at 0x7f825d81ff70>, <matplotlib.lines.Line2D object at 0x7f825d81fbb0>], 'caps': [<matplotlib.lines.Line2D object at 0x7f825d81fd60>, <matplotlib.lines.Line2D object at 0x7f825d81f5e0>], 'boxes': [<matplotlib.lines.Line2D object at 0x7f825b3f04c0>], 'medians': [<matplotlib.lines.Line2D object at 0x7f825d81f250>], 'fliers': [], 'means': []}
red_square = dict(markerfacecolor='r', marker='s')
fig5, ax5 = plt.subplots()
ax5.set_title('Horizontal Boxes')
ax5.boxplot(data, vert=False, flierprops=red_square)
Horizontal Boxes

Out:

{'whiskers': [<matplotlib.lines.Line2D object at 0x7f825b07c400>, <matplotlib.lines.Line2D object at 0x7f8228fa3a60>], 'caps': [<matplotlib.lines.Line2D object at 0x7f8228fa3e50>, <matplotlib.lines.Line2D object at 0x7f8228fa3d60>], 'boxes': [<matplotlib.lines.Line2D object at 0x7f825b07cdf0>], 'medians': [<matplotlib.lines.Line2D object at 0x7f825b3312e0>], 'fliers': [<matplotlib.lines.Line2D object at 0x7f825fd215b0>], 'means': []}
fig6, ax6 = plt.subplots()
ax6.set_title('Shorter Whisker Length')
ax6.boxplot(data, flierprops=red_square, vert=False, whis=0.75)
Shorter Whisker Length

Out:

{'whiskers': [<matplotlib.lines.Line2D object at 0x7f82627134c0>, <matplotlib.lines.Line2D object at 0x7f825ad58610>], 'caps': [<matplotlib.lines.Line2D object at 0x7f825ad582e0>, <matplotlib.lines.Line2D object at 0x7f825ad58700>], 'boxes': [<matplotlib.lines.Line2D object at 0x7f825b3abdf0>], 'medians': [<matplotlib.lines.Line2D object at 0x7f825ad58580>], 'fliers': [<matplotlib.lines.Line2D object at 0x7f826034a8e0>], 'means': []}

Fake up some more data

Making a 2-D array only works if all the columns are the same length. If they are not, then use a list instead. This is actually more efficient because boxplot converts a 2-D array into a list of vectors internally anyway.

data = [data, d2, d2[::2]]
fig7, ax7 = plt.subplots()
ax7.set_title('Multiple Samples with Different sizes')
ax7.boxplot(data)

plt.show()
Multiple Samples with Different sizes

References

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

Total running time of the script: ( 0 minutes 3.490 seconds)

Gallery generated by Sphinx-Gallery