Python Set difference_update() Method with Examples

Prerequisite:

Set difference_update() Method in Python:

The difference_update() method removes items from both sets.

The difference_update() method differs from the difference() method in that the difference() method returns a new set that does not include the unwanted items, whereas the difference_update() method removes the unwanted items from the original set.

For Example

If P and Q are two distinct sets. A set difference between P and Q is a set of elements that exist only in set P but not in set Q.

The difference_update() replaces set P with the P-Q set difference.

Syntax:

set.difference_update(set)

Parameters

set: This is Required. The set used to look for differences.

Return Value:

difference_update() produces a result None, indicating that the object (set) has been mutated.

Let P, Q be two sets

When you execute the code,

The result is None.
P will be updated to P-Q.
Q will remain unchanged.

Examples:

Example1:

Input:

Given first set = {10, 11, 12, 13}
Given second set = {11, 12, 20, 14}

Output:

The given first set is : {10, 13}
The given second set is : {11, 12, 20, 14}
The result after applying difference_update method:  None

Explanation:

Here it removes the common elements{11, 12} from the first set and
updates the given first set as {10, 13}.

Example2:

Input:

Given first set = {20, 30, 40, 20, 30, 50, 60}
Given second set = {40, 50, 60, 100, 80}

Output:

The given first set is : {20, 30}
The given second set is : {100, 40, 80, 50, 60}
The result after applying difference_update method:  None

Set difference_update() Method with Examples in Python

Using Built-in Functions (Static Input)
Using Built-in Functions (User Input)

Method #1: Using Built-in Functions (Static Input)

Approach:

Give the first set as static input and store it in a variable.
Give the second set as static input and store it in another variable.
Apply the difference_update() method to the given first and second sets.
Store it in another variable.
Print the given first set.
Print the second set.
Print the above result after applying the difference_update() method for the given sets.
The Exit of the Program.

Below is the implementation:

# Give the first set as static input and store it in a variable.
fst_Set = {10, 11, 12, 13}
# Give the second set as static input and store it in another variable.
scnd_set = {11, 12, 20, 14}
# Apply the difference_update() method to the given first and second sets.
# Store it in another variable.
rslt = fst_Set.difference_update(scnd_set)
# print the given first set.
print("The given first set is :", fst_Set)
# print the given second set.
print("The given second set is :", scnd_set)
# Print the above result after applying difference_update() method for the given sets.
print("The result after applying difference_update method: ", rslt)

Output:

The given first set is : {10, 13}
The given second set is : {11, 12, 20, 14}
The result after applying difference_update method:  None

Method #2: Using Built-in Functions (User Input)

Approach:

Give the first set as user input using set(),map(),input(),and split() functions.
Store it in a variable.
Give the second set as user input using set(),map(),input(),and split() functions.
Store it in another variable.
Apply the difference_update() method to the given first and second sets.
Store it in another variable.
Print the given first set.
Print the second set.
Print the above result after applying the difference_update() method for the given sets.
The Exit of the Program.

Below is the implementation:

# Give the first set as user input using set(),map(),input(),and split() functions.
# Store it in a variable.
fst_set = set(map(int, input(
   'Enter some random Set Elements separated by spaces = ').split()))
# Give the second set as user input using set(),map(),input(),and split() functions.
# Store it in another variable.
scnd_set = set(map(int, input(
   'Enter some random Set Elements separated by spaces = ').split()))
# Apply the difference_update() method to the given first and second sets.
# Store it in another variable.
rslt = fst_set.difference_update(scnd_set)
# print the given first set.
print("The given first set is :", fst_set)
# print the second first set.
print("The given second set is :", scnd_set)
# Print the above result after applying difference_update method for the given sets.
print("The result after applying difference_update method: ", rslt)

Output:

Enter some random Set Elements separated by spaces = 10 20 15 16
Enter some random Set Elements separated by spaces = 20 15 16 80
The given first set is : {10}
The given second set is : {16, 80, 20, 15}
The result after applying difference_update method: None