How to Perfectly Center Data Labels in Stacked Bar Charts Using Python?

Centering Data Labels in Stacked Bar Charts

When creating a stacked bar chart, it can be challenging to ensure that the data labels are correctly centered within each section of the bar. This issue can arise due to a variety of reasons, such as the height of the bars, the spacing between the bars, and the font size of the labels.

Using Pandas and Matplotlib.pyplot

A robust and concise approach to this problem involves using Pandas and Matplotlib.pyplot. Pandas provides a convenient way to represent and manipulate data, while Matplotlib.pyplot offers a powerful toolset for creating visualizations. Here's how you can center the data labels in a stacked bar chart using this approach:

1. Create a Pandas DataFrame with the data you wish to plot.
2. Use the .plot(stacked=True, kind='bar') method to generate the stacked bar chart.
3. Iterate through the containers within the plot using for c in ax.containers:.
4. Use fmt=lambda x: f'{x:.0f}' if x > 0 else '' to customize the label format, removing decimal places and displaying only non-zero values.
5. Call ax.bar_label(c, fmt=fmt) to center the data labels within each section of the bar.

Using Seaborn

Seaborn, a high-level API built upon Matplotlib, offers an alternative way to create stacked bar charts. Although Seaborn does not directly support stacking, it provides options for creating stacked plots using sns.histplot or sns.displot.

For the figure-level plot using sns.displot, iterate through the axes and then through the containers within each axis. For each container, use ax.bar_label(c, fmt=fmt) to center the data labels.

Original Method with Patches

A method that directly works with Matplotlib.patches.Rectangle objects can be used to extract the values and position of each section of the stacked bar. This method involves:

1. Accessing the list of patches using .patches attribute.
2. Iterating through the patches and extracting the height, width, x-coordinate, and y-coordinate.
3. Calculating the center point of each section and placing the label accordingly.
4. Customizing the label text as needed.

The above is the detailed content of How to Perfectly Center Data Labels in Stacked Bar Charts Using Python?. For more information, please follow other related articles on the PHP Chinese website!