 # Python Set difference()

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

### Example

``````# 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:

``A.difference(B)``

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))``````

Output

```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)``````

Output

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

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