[Python tutorial] part 50 superset of set

In this article, we introduce how to use issuperset() Method to determine whether a set is a superset of another set .

issuperset() Method introduction

For collection A and B, If B All elements in belong to A, that A Namely B Superset or superset of （superset）. here , aggregate B Namely A Subset （subset）. If the collection A It's not equal to the set B,A Namely B It's a super collection .

Logically speaking , Any set is its own superset . The set in the following figure A yes B Superset , Because of the collection B The elements in 1、2、3 All belong to the collection A.

stay Python Can use set issuperset() Method to determine whether a set is a superset of another set ：

set_a.issuperset(set_b)

If set_a yes set_b Superset ,issuperset() Method returns True; otherwise , return False.

issuperset() Method example

The following example uses issuperset() Method to determine the set numbers Is it a collection scores Superset ：

numbers = {
1, 2, 3, 4, 5}
scores = {
1, 2, 3}
result = numbers.issuperset(scores)
print(result)

The output is as follows ：

True

Because of the collection scores All elements in belong to the set numbers, numbers yes scores Superset .

Any set is its own superset , for example ：

numbers = {
1, 2, 3, 4, 5}
result = numbers.issuperset(numbers)
print(result)

The output is as follows ：

True

aggregate scores No numbers Subset , So the following example returns False：

numbers = {
1, 2, 3, 4, 5}
scores = {
1, 2, 3}
result = scores.issuperset(numbers)
print(result)
False

Superset operator

Superset operator （>=） Used to determine whether a set is a superset of another set ：

set_a >= set_b

If the collection set_a Is a collection set_b Superset , The superset operator returns True; otherwise , return False. for example ：

numbers = {
1, 2, 3, 4, 5}
scores = {
1, 2, 3}
result = numbers >= scores
print(result) # True
result = numbers >= numbers
print(result) # True

True superset operator （>） It is used to judge whether a set is a true superset of another set ：

set_a > set_b

for example ：

numbers = {
1, 2, 3, 4, 5}
scores = {
1, 2, 3}
result = numbers > scores
print(result) # True
result = numbers > numbers
print(result) # True

In the example above , aggregate numbers Not its own true superset , therefore > The operator returns False.

summary

• If the collection B All elements of belong to the collection A, aggregate A Namely B Superset .
• A collection of issuperset() Method is used to determine whether a set is a superset of another set .
• Superset operator （>=) And the true superset operator （>） You can also judge whether a set is a superset or a true superset of another set .