Bar Label Demo

This example shows how to use the bar_label helper function to create bar chart labels.

See also the grouped bar, stacked bar and horizontal bar chart examples.

import matplotlib
import matplotlib.pyplot as plt
import numpy as np

Define the data

N = 5
menMeans = (20, 35, 30, 35, -27)
womenMeans = (25, 32, 34, 20, -25)
menStd = (2, 3, 4, 1, 2)
womenStd = (3, 5, 2, 3, 3)
ind = np.arange(N)    # the x locations for the groups
width = 0.35       # the width of the bars: can also be len(x) sequence

Stacked bar plot with error bars

fig, ax = plt.subplots()

p1 = ax.bar(ind, menMeans, width, yerr=menStd, label='Men')
p2 = ax.bar(ind, womenMeans, width,
            bottom=menMeans, yerr=womenStd, label='Women')

ax.axhline(0, color='grey', linewidth=0.8)
ax.set_ylabel('Scores')
ax.set_title('Scores by group and gender')
ax.set_xticks(ind)
ax.set_xticklabels(('G1', 'G2', 'G3', 'G4', 'G5'))
ax.legend()

# Label with label_type 'center' instead of the default 'edge'
ax.bar_label(p1, label_type='center')
ax.bar_label(p2, label_type='center')
ax.bar_label(p2)

plt.show()

Horizontal bar chart

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

# Example data
people = ('Tom', 'Dick', 'Harry', 'Slim', 'Jim')
y_pos = np.arange(len(people))
performance = 3 + 10 * np.random.rand(len(people))
error = np.random.rand(len(people))

fig, ax = plt.subplots()

hbars = ax.barh(y_pos, performance, xerr=error, align='center')
ax.set_yticks(y_pos)
ax.set_yticklabels(people)
ax.invert_yaxis()  # labels read top-to-bottom
ax.set_xlabel('Performance')
ax.set_title('How fast do you want to go today?')

# Label with specially formatted floats
ax.bar_label(hbars, fmt='%.2f')
ax.set_xlim(right=15)  # adjust xlim to fit labels

plt.show()

Some of the more advanced things that one can do with bar labels

fig, ax = plt.subplots()

hbars = ax.barh(y_pos, performance, xerr=error, align='center')
ax.set_yticks(y_pos)
ax.set_yticklabels(people)
ax.invert_yaxis()  # labels read top-to-bottom
ax.set_xlabel('Performance')
ax.set_title('How fast do you want to go today?')

# Label with given captions, custom padding and annotate options
ax.bar_label(hbars, labels=['±%.2f' % e for e in error],
             padding=8, color='b', fontsize=14)
ax.set_xlim(right=16)

plt.show()

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References

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

matplotlib.axes.Axes.bar
matplotlib.pyplot.bar
matplotlib.axes.Axes.barh
matplotlib.pyplot.barh
matplotlib.axes.Axes.bar_label
matplotlib.pyplot.bar_label

Out:

<function bar_label at 0x7f5f32b86e50>