Python Pandas - Sort index values and also return the indices that would sort the index

To sort index values and also return the indices that would sort the index, use the index.sort_values(). The return_indexer parameter is set to be True.

At first, import the required libraries −

import pandas as pd

Creating Pandas index −

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

Display the Pandas index −

print("Pandas Index...\n",index)

Sort index values. By default, sorts in Ascending order. Return the indices to sort the index using the "return_indexer" parameter with value True −

print("\nSort and also return the indices that would sort the index...\n",index.sort_values(return_indexer=True))

Example

Following is the code −

import pandas as pd

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

# Display the Pandas index
print("Pandas Index...\n",index)

# Return the number of elements in the Index
print("\nNumber of elements in the index...\n",index.size)

# Sort index values
# By default, sorts in Ascending order
# Return the indices to sort the index using the "return_indexer" parameter with value True
print("\nSort and also return the indices that would sort the index...\n",index.sort_values(return_indexer=True))

Output

This will produce the following output −

Pandas Index...
Int64Index([50, 10, 70, 95, 110, 90, 30], dtype='int64')

Number of elements in the index...
7

Sort and also return the indices that would sort the index...
(Int64Index([10, 30, 50, 70, 90, 95, 110], dtype='int64'), array([1, 6, 0, 2, 5, 3, 4], dtype=int64))