Sets

Sets¶

• Sets are used to store multiple items in a single variable.
• Sets are unordered, unchangeable (but you can add/remove items), and do not allow duplicate values.

In [1]:

## Creating a Set
fruits_set = {'apple', 'banana', 'cherry'}
print(fruits_set)

## Creating a Set fruits_set = {'apple', 'banana', 'cherry'} print(fruits_set)

{'cherry', 'banana', 'apple'}

Note : Since Set is Unordered, there is no indexing and slicing¶

No Duplicates Allowed¶

In [3]:

## Duplicate values will be removed automatically
fruits_set = {'apple', 'banana', 'apple'}
print(fruits_set)

## Duplicate values will be removed automatically fruits_set = {'apple', 'banana', 'apple'} print(fruits_set)

{'banana', 'apple'}

Add Items¶

In [4]:

fruits_set = {'apple', 'banana'}
fruits_set.add('cherry')
print(fruits_set)

fruits_set = {'apple', 'banana'} fruits_set.add('cherry') print(fruits_set)

{'cherry', 'banana', 'apple'}

Add Multiple Items¶

In [7]:

fruits_set.update(['orange', 'grape'])
print(fruits_set)

fruits_set.update(['orange', 'grape']) print(fruits_set)

{'orange', 'apple', 'cherry', 'banana', 'grape'}

Remove Items¶

In [8]:

fruits_set.remove('banana')
print(fruits_set)

fruits_set.remove('banana') print(fruits_set)

{'orange', 'apple', 'cherry', 'grape'}

Discard vs Remove¶

In [9]:

fruits_set.discard('pineapple')  # No error if not found
# fruits_set.remove('pineapple') would raise an error

fruits_set.discard('pineapple') # No error if not found # fruits_set.remove('pineapple') would raise an error

Set Operations¶

Set Methods in Python¶

Method	Description	Example
add(elem)	Adds a single element to the set	s.add(5)
update(iterable)	Adds multiple elements from an iterable (like list, tuple)	s.update([1, 2])
remove(elem)	Removes specified element; raises error if not found	s.remove(3)
discard(elem)	Removes specified element; no error if element not found	s.discard(10)
pop()	Removes and returns a random element	s.pop()
clear()	Removes all elements from the set	s.clear()
copy()	Returns a shallow copy of the set	s2 = s.copy()
union(set2)	Returns a new set with all elements from both sets	s.union(s2)
intersection(set2)	Returns common elements of both sets	s.intersection(s2)
difference(set2)	Returns elements in the first set but not in the second	s.difference(s2)
symmetric_difference(set2)	Returns elements in either set, but not in both	s.symmetric_difference(s2)
issubset(set2)	Returns True if all elements of the set are in set2	s.issubset(s2)
issuperset(set2)	Returns True if set has all elements of set2	s.issuperset(s2)
isdisjoint(set2)	Returns True if sets have no elements in common	s.isdisjoint(s2)

In [ ]:

# Union
set1 = {'a', 'b'}
set2 = {'b', 'c'}
print(set1.union(set2))

# Union set1 = {'a', 'b'} set2 = {'b', 'c'} print(set1.union(set2))

In [ ]:

# Intersection
print(set1.intersection(set2))

# Intersection print(set1.intersection(set2))

In [ ]:

# Difference
print(set1.difference(set2))

# Difference print(set1.difference(set2))

In [ ]:

# Symmetric Difference
print(set1.symmetric_difference(set2))

# Symmetric Difference print(set1.symmetric_difference(set2))

Looping Through a Set¶

In [10]:

for fruit in fruits_set:
    print(fruit)

for fruit in fruits_set: print(fruit)

orange
apple
cherry
grape

Check if Item Exists¶

In [11]:

'apple' in fruits_set

'apple' in fruits_set

Out[11]:

True

In [ ]: