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Python Pandas CategoricalIndex - Add new categories
To add new categories, use the CategoricalIndex add_categories() method in Pandas. At first, import the required libraries −
import pandas as pd
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)
Add new categories using add_categories(). Set the new categories as a parameter. The new categories will be included at the last/highest place in the categories −
print("\nCategoricalIndex after adding new categories...\n",catIndex.add_categories(["a", "b", "c", "d"]))Example
Following is the code −
import pandas as pd
# CategoricalIndex can only take on a limited, and usually fixed, number of possible values (categories
# 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)
# Add new categories using add_categories()
# Set the new categories as a parameter
# The new categories will be included at the last/highest place in the categories
print("\nCategoricalIndex after adding new categories...\n",catIndex.add_categories(["a", "b", "c", "d"]))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 adding new categories... CategoricalIndex(['p', 'q', 'r', 's', 'p', 'q', 'r', 's'], categories=['p', 'q', 'r', 's', 'a', 'b', 'c', 'd'], ordered=True, dtype='category')
Updated on: 18-Oct-2021
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