Join Sets
Joining sets means combining elements from two or more sets.
Because sets store unique values only, joining sets automatically removes duplicates.
Python supports multiple set operations for joining and comparing sets.
Join Sets Using Union (|)
The union operator combines all unique elements.
python
a = {1, 2, 3}
b = {3, 4, 5}
result = a | b
print(result)
Join Sets Using union()
Returns a new set containing all elements.
python
a = {1, 2, 3}
b = {3, 4, 5}
result = a.union(b)
print(result)
Join Multiple Sets
python
a = {1, 2}
b = {3, 4}
c = {5, 6}
result = a.union(b, c)
print(result)
Update Set with Another Set (update())
Modifies the original set.
python
a = {1, 2}
b = {3, 4}
a.update(b)
print(a)
Join Sets Using Loop
python
a = {1, 2}
b = {3, 4}
for item in b:
a.add(item)
print(a)
Join Sets Using |= Operator
python
a = {1, 2}
b = {3, 4}
a |= b
print(a)
Join Sets with Different Data Types
python
a = {1, 2}
b = {"a", "b"}
print(a.union(b))
Join Frozen Sets
python
fs1 = frozenset([1, 2])
fs2 = frozenset([3, 4])
result = fs1 | fs2
print(result)
Frozen sets cannot be modified.
Common Mistakes
Expecting Order
python
result = {1, 3, 2}
print(result)
Order is not guaranteed.
Using + Operator
python
# a + b # TypeError
Sets do not support concatenation.
Performance Note
- Set union is very fast
- Best used for deduplication
update()is efficient for large datasets
Summary
- Sets join using union operations
|andunion()create new setsupdate()modifies existing set- Duplicates are removed automatically
- Frozen sets support union but not modification