Python

Indexing--  it will help u to fetch single character 

string= "Python"

string[2]

#slicing process of fetching a sub-string from the given string 

#sequence of charater we can fetch means more than 1 character

string="Divyanshu"

string[2:4+1]   #basically here number is index value #string[start_index:end+index+1]

string = "Hunny"   #indexing agr positive hai to left se count hoga #right se negative me

string[:]  #it will give u entire string

#now If i want to any characterwise index like string is Hunny and I want un only

#string[start_index:end_index+1:step]

string[1:4:2]

#reverse your string

#string[:: -1]

string="Baba hunny"

string[:: -1]

# to convert into lowecase

string="New Divyanshu"

new_string=string.lower()  #new_string becase we've to create another string

print(new_string)

s1={1,2,3,4,5}   

s2={3,2,8,67,85}

s3=s1.union(s2)

s3   #isme add hota hai whole value lekin common value update nhi hongi

#intersection - Common element nikalta hai

s3=s1.intersection(s2)

s3

   #it will give u common value 

s1.difference(s2)

#all elements of s2 which are preent in s1 will be removed from s1

s1.symmetric_difference(s2)

#a new set of elements is created after removing elements which are in both union_intersection it will first do union then intersection