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Python Sets
Python sets are unordered collections of unique elements. They are defined using curly braces {} or the set() constructor.
my_set = {1, 2, 3, 3, 4} # Duplicates are automatically removed
print(my_set) # Output: {1, 2, 3, 4}
another_set = set(5, 6, 7) # Creating a set from a list
print(another_set) # Output: {5, 6, 7}
empty_set = set() #Creating an empty set. Note: {} creates an empty dictionary.
print(empty_set) #Output: set()
Key Set Operations:
union()or|: Combines elements from two sets.
set1 = {1, 2, 3}
set2 = {3, 4, 5}
union_set = set1.union(set2) #or set1 | set2
print(union_set) # Output: {1, 2, 3, 4, 5}
intersection()or&: Returns common elements.
intersection_set = set1.intersection(set2) #or set1 & set2
print(intersection_set) # Output: {3}
difference()or-: Returns elements in the first set but not the second.
difference_set = set1.difference(set2) #or set1 - set2
print(difference_set) # Output: {1, 2}
symmetric_difference()or^: Returns elements in either set, but not both.
symmetric_difference_set = set1.symmetric_difference(set2) #or set1 ^ set2
print(symmetric_difference_set) # Output: {1, 2, 4, 5}
add(): Adds an element.
my_set.add(5)
print(my_set)
remove(): Removes an element; raises KeyError if not present.discard(): Removes an element; does nothing if not present.pop(): Removes and returns an arbitrary element.clear(): Removes all elements.issubset(): Checks if one set is a subset of another.issuperset(): Checks if one set is a superset of another.isdisjoint(): Checks if two sets have no common elements.
Frozen Sets Python Sets - Examples
Set Comprehension: Similar to List Comprehension, but creates a set.
squares = {x**2 for x in range(5)}
print(squares) # Output: {0, 1, 4, 9, 16}