Sets in Python

What are the sets?

In Python, a set is a collection of unique elements. It is an unordered, mutable data structure that supports operations like union, intersection, difference, and membership testing.

A set can be defined using the built-in 'set' type. Sets are used to store multiple items in a single variable. 

Set is one of 4 built-in data types in Python used to store collections of data, the other 3 are List, Tuple, and Dictionary, all with different qualities and usage.

Sets properties

Set can be enclosed with curly bracket '{ }' and values inside the set are separated with commas

For example:

 a = {1, 2, 3}
 print(type(a))

 //Output
 <class 'set'>

Python sets are immutable

Sets in Python are immutable You can create a set of numbers and add elements to it. but you cannot change the elements once they have been added to the set.

 numbers = {1, 2, 3, 4} 
 numbers[0] = 5 
 print(numbers) 

 //Output 
 TypeError: 'set' object does not support item assignment

Sets do not contains duplicate entries 

For example:

 a {10, 10, 10}
 print(a)        # only one 10 get stored

 //Output
 {10}

Set can store dissimilar values 

For example:

 a = set()               # empty set, use () instead of {}
 b = {20}                # set with one item
 c = {'John', 3.5, 5}    # set with multiple items
 print(a)
 print(b)
 print(c)

 //Output
 set()
 {20}
 {'John', 3.5, 5}

It is possible to create a set of strings and tuples, but not a set of lists.

For examples:

 numbers = {12, 23, 45, 16, 52}
 print(numbers)
 
 //Output
 {16, 52, 23, 12, 45}

Set slicing

Slicing of sets is not possible in Python because sets are unordered collections of unique elements and don't have indices

Set methods

Function Name	Description
add()	Adds a given element to a set
clear()	Removes all the elements from the set
copy()	Returns a copy of the set
difference()	Returns a set that is the difference beetween two sets
difference_update()	Updates the existing caller set with the difference between two sets
discard()	Removes the element from the set
frozenset()	return an immutable frozenset object
intersection()	Updates the existing caller set with the intersection of sets
intersection_update()	Updates the existing caller set with the intersection of sets
isdisjoint()	Checks whether the sets are disjoint or not
issubset()	Returns True if all elements of a set are present in another set
issubset()	Returns
issuperset()	Returns True if all elements of a set occupies another set
pop()	Returns and removes a random element from the set
remove()	Removes the element from the set
symmetric_difference())	Returns a set which is the symmetric difference between the two sets/td>
symmetric_difference_update()	Updates the existing caller set with the Symmetric difference of sets
union()	Returns a set that has the union of all sets
update()	Adds elements to the set