Python Pandas - Form the Union of two Index objects but do not sort the result

To form the intersection of two Index objects, use the index1.intersection(index2) method in Pandas. To avoid sorting the result, use the sort parameter and set it to False.

At first, import the required libraries −

import pandas as pd

Creating two Pandas index −

index1 = pd.Index([10, 20, 30, 40, 50])
index2 = pd.Index([80, 65, 60, 70, 55])

Display the Pandas index1 and index2 −

print("Pandas Index1...\n",index1)
print("Pandas Index2...\n",index2)

Perform union. We have used the "sort" parameter with value ‘False’ to unsort the results −

res = index1.union(index2, sort=False)

Example

Following is the code −

import pandas as pd

# Creating two Pandas index
index1 = pd.Index([10, 20, 30, 40, 50])
index2 = pd.Index([80, 65, 60, 70, 55])

# Display the Pandas index1 and index2
print("Pandas Index1...\n",index1)
print("Pandas Index2...\n",index2)

# Return the number of elements in Index1 and Index2
print("\nNumber of elements in index1...\n",index1.size)
print("\nNumber of elements in index2...\n",index2.size)

# Perform union
# We have used the "sort" parameter to unsort the results
res = index1.union(index2, sort=False)

# Union of both the indexes
# Results are unsorted
print("\nThe index1 and index2 Union with unsorted result...\n",res)

Output

This will produce the following output −

Pandas Index1...
Int64Index([10, 20, 30, 40, 50], dtype='int64')
Pandas Index2...
Int64Index([80, 65, 60, 70, 55], dtype='int64')

Number of elements in index1...
5

Number of elements in index2...
5

The index1 and index2 Union with unsorted result...
Int64Index([10, 20, 30, 40, 50, 80, 65, 60, 70, 55], dtype='int64')