5. Set operations
Set operations combine two sets and return a new set without changing the originals.
a | b— union: elements that appear inaorb(or both).a & b— intersection: elements that appear in both.a - b— difference: elements inabut not inb.a ^ b— symmetric difference: elements in exactly one of the two sets.
The printed order of a set is not guaranteed, so sorted() is used here to get a stable result.
The same operations are also methods: a.union(b), a.intersection(b), a.difference(b) and a.symmetric_difference(b). Methods accept any iterable, while the operators require both sides to be sets.
set.issubset(other) returns True when every element of the set is also in other:
Coming from JavaScript? Set algebra uses operators: a | b, a & b, a - b, a ^ b. JS Set uses methods such as union() and intersection().
Union
The union a | b contains every element that appears in a or b, without duplicates. Create a = {1, 2, 3} and b = {3, 4}, then print the union in ascending order with sorted(a | b).
Print exactly:
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Intersection
The intersection a & b contains only the elements present in both sets. With a = {1, 2, 3} and b = {3, 4}, print sorted(a & b).
Print exactly:
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Difference
The difference a - b contains the elements of a that are not in b. With a = {1, 2, 3} and b = {3, 4}, print sorted(a - b).
Print exactly:
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Symmetric difference
The symmetric difference a ^ b contains the elements that are in exactly one of the two sets. With a = {1, 2, 3} and b = {3, 4}, print sorted(a ^ b).
Print exactly:
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Use a set method
a.union(other) does the same as a | other but accepts any iterable. Create a = {1, 2, 3} and print sorted(a.union([3, 4, 5])).
Print exactly:
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Check a subset
set.issubset(other) returns True when every element of the set is also in other. Create small = {1, 2} and large = {1, 2, 3}, then print small.issubset(large) and large.issubset(small).
Print exactly:
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