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 0x7f5ddabab8b0>, <matplotlib.lines.Line2D object at 0x7f5ddabab2b0>], 'caps': [<matplotlib.lines.Line2D object at 0x7f5ddababb20>, <matplotlib.lines.Line2D object at 0x7f5ddac11370>], 'boxes': [<matplotlib.lines.Line2D object at 0x7f5ddababc10>], 'medians': [<matplotlib.lines.Line2D object at 0x7f5dd6130be0>], 'fliers': [<matplotlib.lines.Line2D object at 0x7f5ddf32f5b0>], 'means': []}
fig2, ax2 = plt.subplots()
ax2.set_title('Notched boxes')
ax2.boxplot(data, notch=True)
Notched boxes

Out:

{'whiskers': [<matplotlib.lines.Line2D object at 0x7f5ddf2cd700>, <matplotlib.lines.Line2D object at 0x7f5ddf2cd910>], 'caps': [<matplotlib.lines.Line2D object at 0x7f5ddf2cdcd0>, <matplotlib.lines.Line2D object at 0x7f5ddf2cd5b0>], 'boxes': [<matplotlib.lines.Line2D object at 0x7f5dfaf7bc70>], 'medians': [<matplotlib.lines.Line2D object at 0x7f5ddab593a0>], 'fliers': [<matplotlib.lines.Line2D object at 0x7f5ddab59c40>], '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 0x7f5ddf52d5b0>, <matplotlib.lines.Line2D object at 0x7f5ddf52dc10>], 'caps': [<matplotlib.lines.Line2D object at 0x7f5ddf52d430>, <matplotlib.lines.Line2D object at 0x7f5ddf594790>], 'boxes': [<matplotlib.lines.Line2D object at 0x7f5ddf52d730>], 'medians': [<matplotlib.lines.Line2D object at 0x7f5ddf5947f0>], 'fliers': [<matplotlib.lines.Line2D object at 0x7f5ddf5945b0>], '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 0x7f5ddabb30a0>, <matplotlib.lines.Line2D object at 0x7f5ddabb33d0>], 'caps': [<matplotlib.lines.Line2D object at 0x7f5ddabb3730>, <matplotlib.lines.Line2D object at 0x7f5ddabb3a90>], 'boxes': [<matplotlib.lines.Line2D object at 0x7f5ddab68d00>], 'medians': [<matplotlib.lines.Line2D object at 0x7f5ddabb3df0>], '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 0x7f5ddac48100>, <matplotlib.lines.Line2D object at 0x7f5ddac48430>], 'caps': [<matplotlib.lines.Line2D object at 0x7f5ddac48790>, <matplotlib.lines.Line2D object at 0x7f5ddac48af0>], 'boxes': [<matplotlib.lines.Line2D object at 0x7f5ddac23d60>], 'medians': [<matplotlib.lines.Line2D object at 0x7f5ddac48e50>], 'fliers': [<matplotlib.lines.Line2D object at 0x7f5ddac1a1f0>], '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 0x7f5ddf2a91f0>, <matplotlib.lines.Line2D object at 0x7f5ddf2a9520>], 'caps': [<matplotlib.lines.Line2D object at 0x7f5ddf2a9880>, <matplotlib.lines.Line2D object at 0x7f5ddf2a9be0>], 'boxes': [<matplotlib.lines.Line2D object at 0x7f5ddf2b0e50>], 'medians': [<matplotlib.lines.Line2D object at 0x7f5ddf2a9f40>], 'fliers': [<matplotlib.lines.Line2D object at 0x7f5ddf2cf2e0>], '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:

Out:

<function boxplot at 0x7f5dfb00cca0>

Total running time of the script: ( 0 minutes 1.695 seconds)

Keywords: matplotlib code example, codex, python plot, pyplot Gallery generated by Sphinx-Gallery