Useful Set Methods in Python
add(elem)
Adds a unique element to the set. If the element already exists, the set remains unchanged.
Example:
my_set = {1, 2, 3}
my_set.add(4)
print(my_set) # Output: {1, 2, 3, 4}
discard(elem)
Removes a specific element from the set. If the element does not exist, no changes are made and no exception is raised.
Example:
my_set = {1, 2, 3}
my_set.discard(2)
print(my_set) # Output: {1, 3}
remove(elem)
Removes a specific element from the set. If the element does not exist, a KeyError exception is raised.
Example:
my_set = {1, 2, 3}
my_set.remove(2)
print(my_set) # Output: {1, 3}
pop()
Removes and returns an arbitrary element from the set. Since sets are unordered, the removed element is unpredictable. If the set is empty, a KeyError is raised.
Example:
my_set = {1, 2, 3}
element = my_set.pop()
print("Removed element:", element)
print(my_set) # Output: set without the removed element
clear()
Removes all elements from the set, making it empty.
Example:
my_set = {1, 2, 3}
my_set.clear()
print(my_set) # Output: set()
copy()
Returns a shallow copy of the set. Changes made to the copy will not affect the original set.
Example:
my_set = {1, 2, 3}
copy_set = my_set.copy()
copy_set.add(4)
print("Original set:", my_set) # Output: {1, 2, 3}
print("Copied set:", copy_set) # Output: {1, 2, 3, 4}
union(*sets)
Returns a new set containing all unique elements from the given sets. You can also use the | operator for the same operation.
Example:
set1 = {1, 2, 3}
set2 = {3, 4, 5}
union_set = set1.union(set2)
print(union_set) # Output: {1, 2, 3, 4, 5}
intersection(*sets)
Returns a new set containing elements that are common to all the given sets. You can also use the & operator for the same operation.
Example:
set1 = {1, 2, 3}
set2 = {2, 3, 4}
intersection_set = set1.intersection(set2)
print(intersection_set) # Output: {2, 3}
difference(*sets)
Returns a new set containing elements that are in the first set but not in the other given sets. You can also use the – operator for the same operation.
Example:
set1 = {1, 2, 3}
set2 = {2, 3, 4}
difference_set = set1.difference(set2)
print(difference_set) # Output: {1}
symmetric_difference(set)
Returns a new set containing elements that are in either of the sets but not in both. You can also use the ^ operator for the same operation.
Example:
set1 = {1, 2, 3}
set2 = {3, 4, 5}
sym_diff_set = set1.symmetric_difference(set2)
print(sym_diff_set) # Output: {1, 2, 4, 5}
issubset(set)
Returns True if all elements of the set are present in the given set. Otherwise, returns False.
Example:
set1 = {1, 2}
set2 = {1, 2, 3}
print(set1.issubset(set2)) # Output: True
print(set2.issubset(set1)) # Output: False
issuperset(set)
Returns True if all elements of the given set are present in the set. Otherwise, returns False.
Example:
set1 = {1, 2, 3}
set2 = {1, 2}
print(set1.issuperset(set2)) # Output: True
print(set2.issuperset(set1)) # Output: False
isdisjoint(set)
Certainly! Here’s a detailed guide on useful methods for working with sets in Python. Sets are unordered collections of unique elements. They provide various built-in methods to manipulate and query the data they contain.
Useful Set Methods in Python
add(elem)
Adds a unique element to the set. If the element already exists, the set remains unchanged.
Example:
my_set = {1, 2, 3}
my_set.add(4)
print(my_set) # Output: {1, 2, 3, 4}
discard(elem)
Removes a specific element from the set. If the element does not exist, no changes are made and no exception is raised.
Example:
my_set = {1, 2, 3}
my_set.discard(2)
print(my_set) # Output: {1, 3}
remove(elem)
Removes a specific element from the set. If the element does not exist, a KeyError exception is raised.
Example:
my_set = {1, 2, 3}
my_set.remove(2)
print(my_set) # Output: {1, 3}
pop()
Removes and returns an arbitrary element from the set. Since sets are unordered, the removed element is unpredictable. If the set is empty, a KeyError is raised.
Example:
my_set = {1, 2, 3}
element = my_set.pop()
print("Removed element:", element)
print(my_set) # Output: Set without the removed element
clear()
Removes all elements from the set, leaving it empty.
Example:
my_set = {1, 2, 3}
my_set.clear()
print(my_set) # Output: set()
copy()
Returns a shallow copy of the set. Changes made to the copy do not affect the original set.
Example:
my_set = {1, 2, 3}
copy_set = my_set.copy()
copy_set.add(4)
print("Original set:", my_set) # Output: {1, 2, 3}
print("Copied set:", copy_set) # Output: {1, 2, 3, 4}
union(*sets)
Returns a new set containing all unique elements from the given sets. You can also use the | operator for the same operation.
Example:
set1 = {1, 2, 3}
set2 = {3, 4, 5}
union_set = set1.union(set2)
print(union_set) # Output: {1, 2, 3, 4, 5}
intersection(*sets)
Returns a new set containing elements common to all the given sets. You can also use the & operator for the same operation.
Example:
set1 = {1, 2, 3}
set2 = {2, 3, 4}
intersection_set = set1.intersection(set2)
print(intersection_set) # Output: {2, 3}
difference(*sets)
Returns a new set containing elements present in the first set but not in the given sets. You can also use the – operator for the same operation.
Example:
set1 = {1, 2, 3}
set2 = {2, 3, 4}
difference_set = set1.difference(set2)
print(difference_set) # Output: {1}
symmetric_difference(set)
Returns a new set containing elements that are in either of the sets but not in both. You can also use the ^ operator for the same operation.
Example:
set1 = {1, 2, 3}
set2 = {3, 4, 5}
sym_diff_set = set1.symmetric_difference(set2)
print(sym_diff_set) # Output: {1, 2, 4, 5}
issubset(set)
Returns True if all elements of the current set are present in the given set. Otherwise, returns False.
Example:
set1 = {1, 2}
set2 = {1, 2, 3}
print(set1.issubset(set2)) # Output: True
print(set2.issubset(set1)) # Output: False
issuperset(set)
Returns True if all elements of the given set are present in the current set. Otherwise, returns False.
Example:
set1 = {1, 2, 3}
set2 = {1, 2}
print(set1.issuperset(set2)) # Output: True
print(set2.issuperset(set1)) # Output: False
isdisjoint(set)
Returns True if the sets have no elements in common. Otherwise, returns False.
Example:
set1 = {1, 2, 3}
set2 = {4, 5, 6}
set3 = {3, 4, 5}
print(set1.isdisjoint(set2)) # Output: True
print(set1.isdisjoint(set3)) # Output: False
Summary of Useful Methods
- add(elem): Adds a unique element.
- discard(elem): Removes an element without raising an exception if the element does not exist.
- remove(elem): Removes an element and raises an exception if the element does not exist.
- pop(): Removes and returns an arbitrary element.
- clear(): Removes all elements.
- copy(): Creates a shallow copy.
- union(*sets): Union of multiple sets.
- intersection(*sets): Intersection of multiple sets.
- difference(*sets): Difference between sets.
- symmetric_difference(set): Symmetric difference between sets.
- issubset(set): Checks if all elements are in another set.
- issuperset(set): Checks if the set contains all elements of another set.
- isdisjoint(set): Checks if sets have no elements in common.
These methods allow you to efficiently manipulate sets in Python, performing various operations for comparison, modification, and querying.