Simple horizontal bar chart
Syntax:
DataFrame.plot.barh()
The barh() methods accept x and y parameters where x takes the categorical values (by default, it takes the index of the DataFrame) and y takes all the numeric columns. The keyword arguments (like title or figure size) supported by DataFrame.plot() can be passed to the barh() method in order to customize the bar chart. Given is the implementation depicting a horizontal bar chart representing the number of people that preferred particular categories of cuisine.
Example:
Python3
# Import required libraries import pandas as pd # Create a sample dataframe df = pd.DataFrame({'Cuisine': ['Italian', 'Indian', 'Mexican', 'Chinese'], 'Number of People': [20, 25, 15, 10]}) # Plot a bar chart df.plot.barh(x='Cuisine', y='Number of People', title='Cuisine Preference', color='green') |
Output:
Creating Horizontal Bar Charts using Pandas
Prerequisites: Pandas
A bar chart represents categorical data with corresponding data values as rectangular bars. Usually, the x-axis represents categorical values and the y-axis represents the data values or frequencies. This is called a vertical bar chart and the inverse is called a horizontal bar chart. In some cases, a horizontal bar chart provides better readability.
Python has various visualization libraries such as Matplotlib and Seaborn. The Pandas library, having a close integration with Matplotlib, allows creation of plots directly though DataFrame and Series object. This article explores the methods to create horizontal bar charts using Pandas.
Using the plot instance of the Pandas DataFrame, various kinds of graphs can be created including Bar charts. There are two types of bar charts that represent complex categories:
- Grouped or Compounded Bar Charts – When you have sub-categories of a main category, this graph assigns each variable or sub-category with a separate bar in the corresponding category.
- Stacked Bar Charts – When you have sub-categories of a main category, this graph stacks the sub-categories on top of each other to produce a single bar.
The bar() and barh() methods of Pandas draw vertical and horizontal bar charts respectively. Essentially, DataFrame.plot(kind=”bar”) is equivalent to DataFrame.plot.bar(). Below are some examples to create different types of bar charts using the above mentioned functions.