Python Set difference()

1. Overview

The difference() method returns the set difference of two sets.

If A and B are two sets. The set difference of A and B is a set of elements that exists only in set A but not in B. For example:

If A = {1, 2, 3, 4}
B = {2, 3, 9}

Then,
A - B = {1, 4}
B - A = {9}

The syntax of the set difference() method in Python is:

A.difference(B)

Here, A and B are two sets. The following syntax is equivalent to A-B.

2. Return Value from difference()

difference() returns the difference between two sets which is also a set. It doesn’t modify the original sets.

3. Example 1: How difference() works in Python?

A = {'a', 'b', 'c', 'd'}
B = {'c', 'f', 'g'}

# Equivalent to A-B
print(A.difference(B))

# Equivalent to B-A
print(B.difference(A))

Output

{'b', 'a', 'd'}
{'g', 'f'}

You can also find the set difference using - operator in Python.

4. Example 2: Set Difference Using – Operator.

A = {'a', 'b', 'c', 'd'}
B = {'c', 'f', 'g'}

print(A-B)

print(B-A)

Output

{'b', 'd', 'a'} 
{'f', 'g'}