Diverging Bar Chart using Python
Diverging Bar Charts are used to ease the comparison of multiple groups. Its design allows us to compare numerical values in various groups. It also helps us to quickly visualize the favorable and unfavorable or positive and negative responses. The bar chart consisted of a combination of two horizontal bars starting from the middle- one bar extends out from right to left and the other extends out from left to right. The length of the bar is corresponding to the numerical value it represents.
Commonly the two diverging bars are represented with different colors. Values to the left are usually but not necessarily negative or unsatisfactory responses.
Python doesn’t have a particular function to plot diverging bar charts. The alternate way is to use hlines function to draw horizontal lines with a certain value of linewidth to represent them as horizontal bars.
Datasets in use:
Method 1: Using Matplotlib
Approach :
- Import module
- Import or create data
- Preprocess the dataset and clean out the unnecessary noise
- Specify the colors for representing the horizontal bars
- Sort the values in ascending order
- Set the labels for the x-axis and y-axis as well as the title of the chart
- Display the Diverging Bar Chart
Example 1:
Python
import pandas as pd import matplotlib.pyplot as plt import string as str # Creating a DataFrame from the CSV Dataset df = pd.read_csv("car_sales.csv", sep=';') # Separating the Date and Mercedes-Benz Cars unit sales (USA) df['car_sales_z'] = df.loc[:, ['Mercedes-Benz Cars unit sales (USA)']] df['car_sales_z'] = df['car_sales_z'] .str.replace( ',', '').astype(float) # Removing null value df.drop(df.tail(1).index, inplace=True) for i in range(35): # Colour of bar chart is set to red if the sales # is < 60000 and green otherwise df['colors'] = ['red' if float( x) < 60000 else 'green' for x in df['car_sales_z']] # Sort values from lowest to highest df.sort_values('car_sales_z', inplace=True) # Resets initial index in Dataframe to None df.reset_index(inplace=True) # Draw plot plt.figure(figsize=(14, 10), dpi=80) # Plotting the horizontal lines plt.hlines(y=df.index, xmin=60000, xmax=df.car_sales_z, color=df.colors, alpha=0.4, linewidth=5) # Decorations # Setting the labels of x-axis and y-axis plt.gca().set(ylabel='Quarter', xlabel='Sales') # Setting Date to y-axis plt.yticks(df.index, df.Date, fontsize=12) # Title of Bar Chart plt.title('Diverging Bars Chart Example', fontdict={ 'size': 20}) # Optional grid layout plt.grid(linestyle='--', alpha=0.5) # Displaying the Diverging Bar Chart plt.show() |
Output:
Method 2: Using Plotly
Approach:
- Import required libraries
- Create or import data
- Preprocess the Dataset and clean out the unnecessary noise
- Plot the graph using plotly.graph_objects
- Set the labels for the x-axis and y-axis as well as the legend
- Display the Diverging Bar Chart
Example:
Python
import pandas as pd import plotly.graph_objects as go df = pd.read_csv("Tweets.csv") df.head() # Preprocessing the dataset to extract only # the necessary columns categories = [ 'negative', 'neutral', 'positive'] # Construct a pivot table with the column # 'airline' as the index and the sentiments # as the columns gfg = pd.pivot_table( df, index='airline', columns='airline_sentiment', values='tweet_id', aggfunc='count') # Include the sentiments - negative, neutral # and positive gfg = gfg[categories] # Representing negative sentiment with negative # numbers gfg.negative = gfg.negative * -1 df = gfg # Creating a Figure Diverging = go.Figure() # Iterating over the columns for col in df.columns[4:]: # Adding a trace and specifying the parameters # for negative sentiment Diverging.add_trace(go.Bar(x=-df[col].values, y=df.index, orientation='h', name=col, customdata=df[col], hovertemplate="%{y}: %{customdata}")) for col in df.columns: # Adding a trace and specifying the parameters # for positive and neutral sentiment Diverging.add_trace(go.Bar(x=df[col], y=df.index, orientation='h', name=col, hovertemplate="%{y}: %{x}")) # Specifying the layout of the plot Diverging.update_layout(barmode='relative', height=400, width=700, yaxis_autorange='reversed', bargap=0.5, legend_orientation='v', legend_x=1, legend_y=0 ) Diverging |
Output:
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