Example showing a way to create a grouped matplotlib bar chart?

Question

Can I have an example showing a way to create a grouped bar chart with Matplotlib and also how to annotate bars with labels? Thank you.

Answer 1

You can use the below-mentioned code to solve your problem:

import matplotlib

import matplotlib.pyplot as plt

import numpy as np

men_means, men_std = (20, 35, 30, 35, 27), (2, 3, 4, 1, 2)

women_means, women_std = (25, 32, 34, 20, 25), (3, 5, 2, 3, 3)

ind = np.arange(len(men_means))  # the x locations for the groups

width = 0.35  # the width of the bars

fig, ax = plt.subplots()

rects1 = ax.bar(ind - width/2, men_means, width, yerr=men_std,

                label='Men')

rects2 = ax.bar(ind + width/2, women_means, width, yerr=women_std,label='Women')

# Add some text for labels, title and custom x-axis tick labels, etc.

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()

def autolabel(rects, xpos='center'):

    """

    Attach a text label above each bar in *rects*, displaying its height.

    *xpos* indicates which side to place the text w.r.t. the center of

    the bar. It can be one of the following {'center', 'right', 'left'}.

    """

    ha = {'center': 'center', 'right': 'left', 'left': 'right'}

    offset = {'center': 0, 'right': 1, 'left': -1}

    for rect in rects:

        height = rect.get_height()

        ax.annotate('{}'.format(height),

        xy=(rect.get_x() + rect.get_width() / 2, height),

        xytext=(offset[xpos]*3, 3),  # use 3 points offset

        textcoords="offset points",  # in both directions

        ha=ha[xpos], va='bottom')

autolabel(rects1, "left")

autolabel(rects2, "right")

fig.tight_layout()

plt.show()

To know more about this you can have a look at the following video:-