Python Pandas - Return a sorted copy of the index in descending order

To return a sorted copy of the index in descending order, use the index.sort_values() method in Pandas. Set the ascending parameter to False to sort in descending order.

Syntax

Index.sort_values(ascending=True, return_indexer=False, key=None)

Parameters

The main parameters are:

• ascending: Boolean, default True. If False, sort in descending order
• return_indexer: Boolean, default False. If True, returns the indices that would sort the index
• key: Function, optional. Apply function before sorting

Example

Let's create a Pandas index and sort it in descending order:

import pandas as pd

# Creating Pandas index
index = pd.Index([50, 10, 70, 95, 110, 90, 30])

# Display the original index
print("Original Pandas Index:")
print(index)

# Sort index values in descending order
sorted_index = index.sort_values(ascending=False)
print("\nSorted index (descending order):")
print(sorted_index)

Original Pandas Index:
Index([50, 10, 70, 95, 110, 90, 30], dtype='int64')

Sorted index (descending order):
Index([110, 95, 90, 70, 50, 30, 10], dtype='int64')

Sorting String Index

The method also works with string indices:

import pandas as pd

# Creating string index
str_index = pd.Index(['zebra', 'apple', 'mango', 'banana'])

print("Original string index:")
print(str_index)

# Sort in descending order
sorted_str = str_index.sort_values(ascending=False)
print("\nSorted string index (descending):")
print(sorted_str)

Original string index:
Index(['zebra', 'apple', 'mango', 'banana'], dtype='object')

Sorted string index (descending):
Index(['zebra', 'mango', 'banana', 'apple'], dtype='object')

Key Points

• The sort_values() method returns a new sorted copy and doesn't modify the original index
• Set ascending=False for descending order
• Works with numeric, string, and datetime indices
• The original index remains unchanged

Conclusion

Use index.sort_values(ascending=False) to get a sorted copy of the index in descending order. This method preserves the original index while returning a new sorted version.