The set.union(*others) method in Python is used to return a new set that is the union of the original set and one or more other sets (or iterables). The union operation combines all unique elements from both sets, ensuring that no duplicates are present in the resulting set.

Syntax

set.union(*others)

• *others: This can be one or more sets or any iterable (like lists, tuples, or dictionaries) whose elements will be included in the union.

Return Value

• The method returns a new set containing all unique elements from the original set and the specified sets or iterables.

Example

Here are some examples to illustrate how set.union() works:

1. Basic Example with Two Sets

# Creating two sets
set1 = {1, 2, 3}
set2 = {3, 4, 5}

# Performing union
result_set = set1.union(set2)

print(result_set)  # Output: {1, 2, 3, 4, 5}

2. Union with Multiple Sets

You can perform a union with multiple sets or iterables:

# Creating multiple sets
set1 = {1, 2}
set2 = {3, 4}
set3 = {5, 6}

# Performing union with multiple sets
result_set = set1.union(set2, set3)

print(result_set)  # Output: {1, 2, 3, 4, 5, 6}

3. Union with Iterables

You can also use iterables, such as lists or tuples, to perform the union operation:

# Creating a set and a list
set1 = {1, 2, 3}
list1 = [3, 4, 5]

# Performing union with a list
result_set = set1.union(list1)

print(result_set)  # Output: {1, 2, 3, 4, 5}

4. Using the | Operator

You can also use the | operator as a shorthand for performing a union:

set1 = {1, 2, 3}
set2 = {3, 4, 5}

# Performing union using the | operator
result_set = set1 | set2

print(result_set)  # Output: {1, 2, 3, 4, 5}

Use Cases

• Combining Data: Useful for merging different datasets or collections of unique items where you want to ensure no duplicates.
• Data Analysis: Commonly used in data processing and analysis to aggregate results from different sources.
• Set Operations: A fundamental operation in set theory and related algorithms.

Summary

The set.union(*others) method is a powerful tool in Python for combining sets and iterables into a single set containing all unique elements. This method is versatile, allowing for the inclusion of multiple sets or any iterable, and it can be used in conjunction with the | operator for a more concise syntax. Its primary utility lies in data management and manipulation where ensuring uniqueness is important.