How to write text above the bars on a bar plot (Python)?

Question

I have this graph: I want to write the count above each column. These values are in the first and second lists. Can you help me solve this problem? I tried something without success.

This is the code for the graph:

countListFast = [1492.0, 497.0, 441.0, 218.0, 101.0, 78.0, 103.0]
countListSlow = [1718.0, 806.0, 850.0, 397.0, 182.0, 125.0, 106.0]

errorRateListOfFast = ['9.09', '9.09', '9.38', '9.40', '7.89', '8.02', '10.00']
errorRateListOfSlow = ['10.00', '13.04', '14.29', '12.50', '14.29', '14.53', '11.11']

opacity = 0.4
bar_width = 0.35

plt.xlabel('Tasks')
plt.ylabel('Error Rate')
plt.xticks(range(len(errorRateListOfFast)),('[10-20)', '[20-30)', '[30-50)', '[50-70)','[70-90)', '[90-120)', ' [120 < )'), rotation=30)
        plt.bar(np.arange(len(errorRateListOfFast))+ bar_width, errorRateListOfFast, bar_width, align='center', alpha=opacity, color='b', label='Fast <= 6 sec.')
plt.bar(range(len(errorRateListOfSlow)), errorRateListOfSlow, bar_width, align='center', alpha=opacity, color='r', label='Slower > 6 sec.')
plt.legend()
plt.tight_layout()
plt.show()

Does this answer your question? [Adding value labels on a matplotlib bar chart](https://stackoverflow.com/questions/28931224/adding-value-labels-on-a-matplotlib-bar-chart) — Patrick FitzGerald, Jan 05 '21 at 21:13

Martin Evans · Accepted Answer · 2021-06-08T07:57:58.193

plt.bar() returns a list of rectangles that can be used to position suitable text above each of the bars as follows:

import matplotlib.pyplot as plt
import numpy as np

errorRateListOfFast = ['9.09', '9.09', '9.38', '9.40', '7.89', '8.02', '10.00']
errorRateListOfSlow = ['10.00', '13.04', '14.29', '12.50', '14.29', '14.53', '11.11']

# Convert to floats
errorRateListOfFast = [float(x) for x in errorRateListOfFast]
errorRateListOfSlow = [float(x) for x in errorRateListOfSlow]

opacity = 0.4
bar_width = 0.35

plt.xlabel('Tasks')
plt.ylabel('Error Rate')

plt.xticks(range(len(errorRateListOfFast)),('[10-20)', '[20-30)', '[30-50)', '[50-70)','[70-90)', '[90-120)', ' [120 < )'), rotation=30)
bar1 = plt.bar(np.arange(len(errorRateListOfFast)) + bar_width, errorRateListOfFast, bar_width, align='center', alpha=opacity, color='b', label='Fast <= 6 sec.')
bar2 = plt.bar(range(len(errorRateListOfSlow)), errorRateListOfSlow, bar_width, align='center', alpha=opacity, color='r', label='Slower > 6 sec.')

# Add counts above the two bar graphs
for rect in bar1 + bar2:
    height = rect.get_height()
    plt.text(rect.get_x() + rect.get_width() / 2.0, height, f'{height:.0f}', ha='center', va='bottom')

plt.legend()
plt.tight_layout()
plt.show()

Giving you:

ha='center' and va='bottom' refer to how the text is aligned in relation to the x and y co-ordinates, i.e. horizontal and vertical alignment.

score 8 · Answer 2 · answered Nov 08 '16 at 14:55

8

Check out the following link, it may help:

http://matplotlib.org/examples/api/barchart_demo.html

answered Nov 08 '16 at 14:55

lcastillov

2,163
1
11
17

and in the above example, what's this ha='center', va='bottom' - what's it's significance, if you can specify. – Debashis Sahoo Aug 20 '18 at 06:00

score 7 · Answer 3 · answered Feb 02 '22 at 12:58

7

Today you can use this simple snippet:

ax = plt.bar(...)
ax.bar_label(ax.containers[0])

answered Feb 02 '22 at 12:58

igorkf

3,159
2
22
31

How to write text above the bars on a bar plot (Python)?

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