Python set difference_update() usage and examples

Méthodes de collection en Python

Difference_update() uses the difference set of the set to update the set, and calls the difference_update() method.

If A and B are two groups of sets. The difference set of A and B is a set of elements that only exist in set A but not in set B.

For more information, please visitPython set difference.

The syntax of Difference_update() is:

A.difference_update(B)

Here, A and B are two sets. Difference_update() uses A-B's set difference updates the A set.

Difference_update() return value

difference_update() returns None, indicating that the object (set) has changed.

Assuming

result　=　A.difference_update(B)

When you run the code

• result will be None

• A will be equal to A-B

• B will remain unchanged

Example: How does difference_update() work?

A　=　{'a',　'c',　'g',　'd'}
B　=　{'c',　'f',　'g'}
result　=　A.difference_update(B)
print('A　=　',　A)
print('B　=　',　B)
print('result　=　',　result)

When running the program, the output is:

A　=　　{'d',　'a'}
B　=　　{'c',　'g',　'f'}
result　=　　None

Méthodes de collection en Python