Example 1: python set &
>>> A = {0, 2, 4, 6, 8};
>>> B = {1, 2, 3, 4, 5};
>>> print("Union :", A | B)
Union : {0, 1, 2, 3, 4, 5, 6, 8}
>>> print("Intersection :", A & B)
Intersection : {2, 4}
>>> print("Difference :", A - B)
Difference : {0, 8, 6}
# elements not present both sets
>>> print("Symmetric difference :", A ^ B)
Symmetric difference : {0, 1, 3, 5, 6, 8}
Example 2: set in java
SET: Can only store unique values,
And does not maintain order
- HashSet can have null, order is not guaranteed
- LinkedHashSet can have null and keeps the order
- TreeSet sorts the order and don't accept null
Example 3: set in python
A_Set = {1, 2, "hi", "test"}
for i in A_Set: #Loops through the set. You only get the value not the index
print(i) #Prints the current value
Example 4: when to use set
When to use List, Set and Map?
If we need to access elements frequently by using index, then List is a way
to go ArrayList provides faster access if we know index.
If we want to store elements and want them to maintain an order,
then go for List again. List is an ordered collection and maintain order.
If we want to create collection of unique elements and don't want
any duplicate than choose any Set implementation. (HashSet... )
If we want store data in form Key and Value than Map is the way to go.
We can choose from HashMap, Hashtable...
Example 5: how to define a set
emptySet = set()