Rename Categories in CategoricalIndex using Python Pandas

To rename categories, use the CategoricalIndex rename_categories() method in Pandas. At first, import the required libraries −

import pandas as pd

CategoricalIndex can only take on a limited,and usually fixed, number of possible values. Set the categories for the categorical using the "categories" parameter. Treat the categorical as ordered using the "ordered" parameter −

catIndex = pd.CategoricalIndex(["p", "q", "r", "s","p", "q", "r", "s"], ordered=True, categories=["p", "q", "r", "s"])

Rename categories. Set the new categories that will replace the old categories −

print("\nCategoricalIndex after renaming categories...\n",catIndex.rename_categories([5, 10, 15, 20]))

Example

Following is the code −

import pandas as pd

# CategoricalIndex can only take on a limited, and usually fixed, number of possible values
# Set the categories for the categorical using the "categories" parameter
# Treat the categorical as ordered using the "ordered" parameter
catIndex = pd.CategoricalIndex(["p", "q", "r", "s","p", "q", "r", "s"], ordered=True, categories=["p", "q", "r", "s"])

# Display the CategoricalIndex
print("CategoricalIndex...\n",catIndex)

# Get the categories
print("\nDisplayingCategories from CategoricalIndex...\n",catIndex.categories)

# Rename categories
# Set the new categories that will replace the old categories
print("\nCategoricalIndex after renaming categories...\n",catIndex.rename_categories([5, 10, 15, 20]))

Output

This will produce the following output −

CategoricalIndex...
CategoricalIndex(['p', 'q', 'r', 's', 'p', 'q', 'r', 's'], categories=['p', 'q', 'r', 's'], ordered=True, dtype='category')

DisplayingCategories from CategoricalIndex...
Index(['p', 'q', 'r', 's'], dtype='object')

CategoricalIndex after renaming categories...
CategoricalIndex([5, 10, 15, 20, 5, 10, 15, 20], categories=[5, 10, 15, 20], ordered=True, dtype='category')