Set in Python

Set is a collection of finite elements, It does not contain any sequence(index) and it displays elements randomly.
Set displays unique elements and it will be declared using    {}  and Set().

Syntax of Set:-

var = {item1,item2, item3, ...}

var = set();
Example:-

x = {"C","CPP","DS","PHP","Java",".NET"}

or

x = set({"C","CPP","DS","PHP","Java",".NET"})

Example of Set:-
x = {"C","CPP","DS","PHP","Java",".NET","C","CPP"}

for data in x:
   print(data)
How to add elements in Set from User Input?

Note:- Python use {} to declare dictionary and set both but {} is especially for dictionary hence to declare an empty set we should use set().

x = set()

size = int(input("enter size of set"))

for i in range(0,size):

    item = input("Enter item")

    x.add(item)

print("Set elements is ")

for i in x:

    print(i)

Where we use to set in python:-
1) When we want to display random elements then we can use set
2)  When we want to display unique elements then we can use set
for example, OTP is a random number it can be implemented by Set.
Predefined Method Of Set:-
x = {"C","CPP","DS","PHP","Java",".NET","C","CPP"}

1)  add() :-   It is used to add elements in set

      x.add("PYTHON")

2)  remove():-  It is used to remove an element in the set

     x.remove("C")

3)  max(),min():-  it return max and minimum element

     print(max(x))
     print(min(x))
4) sum():-    It is used to calculate the sum of set elements
     print(sum(x))
5)   union():-   It is used to combine two different subsets in a set.
    a = {1,2,3,4}
    b =  {2,3,7,8,9}
    c= a.union(b)
6)  intersection():- It will return common elements from set

      a = {1,2,3,4}
      b =  {2,3,7,8,9}

      c= a.intersection(b)
7) difference():-   It is used to use minus operation in the set means the elements which will exist under x will be removed from y.
      a = {1,2,3,4}
      b =  {2,3,7,8,9}
      c= a.difference(b)
  Complete Example of Set Using Program:-
x = {1,12,23,34,45,11,3}
y = {2,3}
x.add(9)
x.remove(1)
print(max(x))
print(min(x))
print(sum(x))
print(x.union(y))
print(y.union(x))
print(x.intersection(y))
print(x.difference(y))
print("data is ")
for data in x:
   print(data)
  ASSIGNMENT of SET:-

1)  WAP to find the max element in a set not using max()?
2)  WAP to reverse set elements (if random then display actual random and reverse of random elements)?

 s={3,11,23,34,56,1,78,19,17,98,1}

s1 = [int]*len(s)
c=0
for i in s:
   s1[c]=i
   c=c+1
for i in range(len(s)-1,-1,-1):
  print(s1[i])

3)  WAP to display prime element in Set?

What is Frozenset?
This is the special set in python that can not be modified. means it is an immutable set. means we can not add and remove elements.

a = frozenset({1,2,3})

for d in a:

    print(d)