Set (set):
A set in Python is an unordered collection of unique elements. This means no duplicates are allowed, and the order of elements is not preserved.
- Sets are defined using curly braces {} or the set() function.
- Sets are mutable, meaning you can add or remove elements after creation.
- Sets do not support indexing or slicing because they are unordered.
1.) Accessing Elements::
Since sets are unordered, elements are accessed using loops.
Example:
s = {1, 2, 3}
for item in s:
print(item)2.) Adding Items:
Use the add() method to insert a new element.
Example:
s = {1, 2}
s.add(3)
print(s) # Output: {1, 2, 3}3.) Removing Items:
- remove(item): Removes an element; raises error if not found.
- discard(item): Removes an element; does not raise error if not found.
Example:
s = {1, 2, 3}
s.remove(2)
s.discard(5) # No error even if 5 not in set
print(s) # Output: {1, 3}4.) Set Operations:
Example:
s1 = {1, 2, 3}
s2 = {3, 4, 5}
print(s1 | s2) # Union: {1, 2, 3, 4, 5}
print(s1 & s2) # Intersection: {3}
print(s1 - s2) # Difference: {1, 2}Frozenset (frozenset):
A frozenset is an immutable version of a set. Once created, its elements cannot be changed, i.e., you can’t add or remove items.
- Created using the frozenset() function.
- Useful when you need a set that should not be modified (e.g., for dictionary keys or as constants).
Example:
fs = frozenset([1, 2, 3])
print(fs) # Output: frozenset({1, 2, 3})
# fs.add(4) will raise an error