Python Set difference()

In this tutorial, you will learn about the Python Set difference() method with the help of examples.

The difference() method computes the difference of two sets and returns items that are unique to the first set.


# sets of numbers
A = {1, 3, 5, 7, 9}
B = {2, 3, 5, 7, 11}

# returns items present only in set A print(A.difference(B))
# Output: {1, 9}

difference() Syntax

The syntax of the difference() method is:


Here, A and B are two sets.

difference() Parameter

The difference() method takes a single argument:

  • B - a set whose items are not included in the resulting set

difference() Return Value

The difference() method returns:

  • a set with elements unique to the first set

Example 1: Python Set difference()

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))


Set Difference (A - B) = {'b', 'a', 'd'}
Set Difference (B - A) = {'g', 'f'}

In the above example, we have used the difference() method to compute the set differences of two sets A and B. Here,

  • A.difference(B) - returns a set with elements unique to set A
  • B.difference(A) - returns a set with elements unique to set B

Note: Mathematically, the operation A.difference(B) is equivalent to A - B.

Example 2: Set Difference Using - Operator

We can also find the set difference using - operator in Python. For example,

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

# prints the items of A that are not present in B
print(A - B)

# prints the items of B that are not present in A
print(B - A)


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

Here, we have used the - operator to compute the set difference of two sets A and B.

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