Data Virtualization by Python - Group Bar Charts

 # Importing pandas, numpy and matplotlib

import pandas as pd

import numpy as np

from  matplotlib import pyplot as plt

# Importing excel

Mydata7 = pd.read_excel('D:\\file path\\file name.xlsx')

Mydata7

# Creating group bar chars (two bars)

fig, ax = plt.subplots(1,1, figsize = (8,6))

nnnz = Mydata7 ['City Population']

x = np.arange (len(nnnz))

#set a width for each bar 

width = 0.3

A = ax.bar(x - width/2 , Mydata7[2019], width, label='2019',color='green')

B = ax.bar(x + width/2 , Mydata7[2020], width, label='2020',color= 'orange')

#set the ticks (This show site name in x axis)

ax.set_xticks(x)

ax.set_xticklabels(nnnz)

#add the legend       #using the labels of the bars

ax.legend (title = "City Population",fontsize = 10,title_fontsize = 12)

#--------------------------------------------------------------------------

# Creating grouped bar charts (3 bars)

#create the base axis

fig, ax = plt.subplots(1,1, figsize = (9,6))

#set the label   #and the x positions

label = Mydata7 ["City Population"]

x = np.arange(len(label))

#set the width of the bars

width = 0.2

#create the first bar -1 width

rect1 = ax.bar (x - width, Mydata7 [2019],  width = width, label = 2019, edgecolor = "black", color ='#6495ED')   

#create the second bar using x

rect2 = ax.bar (x , Mydata7 [2020] , width = width , label = 2020 , edgecolor = "black", color= '#FFB90F')

#create the third bar plus 1 width

rect3 = ax.bar (x + width ,  Mydata7 [2021] , width = width , label = 2021 , edgecolor = "black", color='#006400')

           

#add the labels to the axis

ax.set_ylabel ("Population", fontsize = 14, labelpad = 12)          

ax.set_xlabel ("City", fontsize = 14, labelpad =12)      

ax.set_title("Population of the Cities",fontsize = 18,pad = 12)            

            

#set the ticks      #using the labels

ax.set_xticks(x)

ax.set_xticklabels(label)

#add the legend

ax.legend(title = "City Population", fontsize = 12,title_fontsize = 12,bbox_to_anchor = (1.0, 1)) 

#adjust the tick paramaters         

ax.tick_params(axis = "x",which = "both",labelrotation = 45,labelsize = 12)   

ax.tick_params(axis = "y",which = "both",labelsize = 12)

#----------------------------------------------

# Adding text label in each bar

# This code need to put below after creating bar charts

for bar in ax.patches:

  # The text annotation for each bar should be its height.

  bar_value = bar.get_height()

  # Format the text with commas to separate thousands. You can do

  # any type of formatting here though.

  text = f'{bar_value:,}'

  # This will give the middle of each bar on the x-axis.

  text_x = bar.get_x() + bar.get_width() / 2

  # get_y() is where the bar starts so we add the height to it.

  text_y = bar.get_y() + bar_value

  # If we want the text to be the same color as the bar, we can

  # get the color like so:

  bar_color = bar.get_facecolor()

  # If you want a consistent color, you can just set it as a constant, e.g. #222222

  ax.text (text_x, text_y, text, ha='center', va='bottom', color=bar_color, size=10)

Source data table :

City Population	2019	2020	2021
Yangon	300,000	312,000	350,000
Mandalay	270,000	290,000	310,000
Sagaing	160,000	170,000	190,000
MonYwar	180,000	190,000	210,000
Harkhar	90,000	100,000	110,000
Loikaw	140,000	150,000	160,000

Reference Websites :

https://towardsdatascience.com/easy-grouped-bar-charts-in-python-b6161cdd563d

https://www.pythoncharts.com/matplotlib/grouped-bar-charts-matplotlib/