.intersection()

The .intersection() method returns a new set with objects that exist inside two or more sets. It’s a fundamental set operation that mirrors the mathematical concept of intersection. This method is widely used in data analysis, filtering datasets, and identifying shared elements between collections. Its ability to operate on multiple sets at once makes it a concise and efficient tool for comparing groups of data.

Here is a Venn diagram that shows how the .intersection() method finds the intersection of multiple sets:

Syntax

set.intersection(set1, set2, ..., setN)

Alternatively:

set & set1 & set2 ... & setN

Parameters:

• set: The input set in which to search for common values.
• set1, set2, ..., setN: The other sets in which to search for common values.

Return Value:

The .intersection() method returns a new set with values that exist inside the given sets.

Example 1: Using .intersection() with Two Sets

In this example, a set of mutual_friends is created with the .intersection() method using two sets of friend groups:

# Create two sets of friend groups
friend_group_1 = {'Juan', 'Mary', 'David', 'Yukiko', 'Alice'}
friend_group_2 = {'Yukiko', 'Peter', 'Juan', 'Alice'}

# Find the mutual friends in these sets
mutual_friends = friend_group_1.intersection(friend_group_2)

# Print the result
print(mutual_friends)

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The output for the example will be:

{'Juan', 'Yukiko', 'Alice'}

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Example 2: Using .intersection() with Three or More Sets

In this example, the .intersection() method finds the intersection of three sets:

# Create three sets
base_set = {1, 2, 3, 4}
base_set1 = {2, 3, 5}
base_set2 = {0, 2, 3, 7}

# Find the intersection of these sets
res = base_set.intersection(base_set1, base_set2)

# Print the result
print(res)

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The output for the example will be:

{2, 3}

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Codebyte Example: Using .intersection() with Non-Set Iterables

In this codebyte example, the .intersection() method converts all the non-set iterables to sets and then finds the intersection of all the sets:

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Frequently Asked Questions

1. Can I chain multiple .intersection() calls?

Yes, you can chain .intersection() calls to find the intersection of multiple sets or iterables. Each call returns a new set with the intersected result.

2. Does .intersection() modify the original set?

No, .intersection() returns a new set and does not change the original set. Use .intersection_update() to modify the original.

3. What happens if I use .intersection() with no arguments?

If used with no arguments, .intersection() returns a shallow copy of the original set, which is a new set containing the same elements as the original.