Python issuperset() Method

The issuperset() Method in Python

To check if a set A is a superset of set B in Python, use the issuperset() method.

For instance:

A = {1, 2, 3, 4, 5, 6}
B = {1, 2, 3}

print(A.issuperset(B))

Result:

True

You can also use the built-in comparison operators to check for supersets in Python.

For instance, to check if set A is a superset of B, use the less than or equal >= operator:

A = {1, 2, 3, 4, 5, 6}
B = {1, 2, 3}

print(A >= B)

Result:

True

A Word on Set Theory

Say you have two sets A and B.

  • Set A is a superset of B if all the elements of set B are in set A.
  • Set A set is always a superset of itself.
  • Set A is a proper superset of B if set A is a superset of set B and the set A has elements B does not.

Here is a Venn diagram of set A being a (proper) superset of set B:

The issuperset() Method in Python
A is a proper superset of B

How to Check If a Set Is a Superset in Python

In Python, there is an issuperset() method you can use to check if a set is a superset of another set.

Here is the syntax:

A.issuperset(B)

This returns True if A is a superset of B. Otherwise, it returns False.

Alternatively, you can also use comparison operators to do the same:

A >= B

For instance:

A = {1, 2, 3, 4, 5, 6}
B = {1, 2, 3}

print(A.issuperset(B))

# Or
print(A >= B)

Result:

True
True

A Set Is a Superset of Itself

A set is always a superset of itself.

You can use the issuperset() method to verify this:

A = {1, 2, 3}

print(A.issuperset(A))

# Or
print(A >= A)

Output:

True
True

How to Check If a Set Is a Proper Superset in Python

Set A is a proper superset of set B if all the elements of set B are in set A and set A has element(s) that set B does not have.

In Python, there is no dedicated method to check if a set is a proper subset of another set.

To check if a set is a proper superset of another set, use the less-than comparison operator:

A = {1, 2, 3, 4, 5, 6}
B = {1, 2, 3}

# Proper superset
print(A > B)

Output:

True

Conclusion

Today you learned how to use issuperset() method in Python. You also learned some basic set theory.

  • Set A is a superset of set B if set A has all the elements of set B.
  • Set A is a proper superset of B if all elements of set B are in set A but set A has at least one element that set B does not.
  • A set is always a superset of itself.

In Python, you can check if set A is a superset of set B by:

  • A.issuperset(B)
  • A >= B

To check if a set A is a proper superset of set B:

  • A > B

Thanks for reading. I hope you find it useful.

Happy coding!

Further Reading

The issubset() Method in Python

Python Advanced Features

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