Join Sets
There are several ways to join two or more sets in Python.
The union() and update() methods joins all items from both sets.
The intersection() method keeps ONLY the duplicates.
The difference() method keeps the items from the first set that are not in the other set(s).
The symmetric_difference() method keeps all items EXCEPT the duplicates.
Union
The union() method returns a new set with all items from both sets.
Example
set1 = {"a", "b", "c"}
set2 = {1, 2, 3}
set3 = set1.union(set2)
print(set3)You can use the | operator instead of the union() method, and you will get the same result.
|Join Multiple Sets
All the joining methods and operators can be used to join multiple sets.
When using a method, just add more sets in the parentheses, separated by commas:
union()When using the | operator, separate the sets with more | operators:
|Join a Set and a Tuple
The union() method allows you to join a set with other data types, like lists or tuples.
The result will be a set.
Example
x = {"a", "b", "c"}
y = (1, 2, 3)
z = x.union(y)
print(z)Note
The | operator only allows you to join sets with sets, and not with other data types like you can with the union() method.
Update
The update() method inserts all items from one set into another.
The update() changes the original set, and does not return a new set.
update()Note
Both union() and update() will exclude any duplicate items.
Intersection
Keep ONLY the duplicates
The intersection() method will return a new set, that only contains the items that are present in both sets.
Example
set1 = {"apple", "banana", "cherry"}
set2 = {"google", "microsoft", "apple"}
set3 = set1.intersection(set2)
print(set3)You can use the & operator instead of the intersection() method, and you will get the same result.
&Note
The & operator only allows you to join sets with sets, and not with other data types like you can with the intersection() method.
The intersection_update() method will also keep ONLY the duplicates, but it will change the original set instead of returning a new set.
set1The values True and 1 are considered the same value. The same goes for False and 0 .
TrueDifference
The difference() method will return a new set that will contain only the items from the first set that are not present in the other set.
Example
set1 = {"apple", "banana", "cherry"}
set2 = {"google", "microsoft", "apple"}
set3 = set1.difference(set2)
print(set3)You can use the - operator instead of the difference() method, and you will get the same result.
-Note
The - operator only allows you to join sets with sets, and not with other data types like you can with the difference() method.
The difference_update() method will keep the items from the first set that are not in the other set, but it will change the original set instead of returning a new set.
difference_update()Symmetric Differences
The symmetric_difference() method will keep only the elements that are NOT present in both sets.
Example
set1 = {"apple", "banana", "cherry"}
set2 = {"google", "microsoft", "apple"}
set3 = set1.symmetric_difference(set2)
print(set3)You can use the ^ operator instead of the symmetric_difference() method, and you will get the same result.
^Note
The ^ operator only allows you to join sets with sets, and not with other data types like you can with the symmetric_difference() method.
The symmetric_difference_update() method will also keep all but the duplicates, but it will change the original set instead of returning a new set.
symmetric_difference_update()