Set Operations

Lets see some operations we can use with sets. We apply these to set to get new sets. We’ll see Union (∪), Intersection (∩), and Relative (\) and Absolute (Ac) Compliment.

Watch the video and then answer the questions below.

Eleven-minute video

You can also view this video on YouTube

Set Operations in Java

The java.util.Set interface does not provide the union (∪), intersection (∩), or difference (\) operations. These would need to be implemented yourself.

Set Operations in Python

Helpfully, Python contains all the basic set operations built in.

Set union (∪) uses the union() method.

set_a = {"a", "b", "c"}
set_b = {"b", "c", "d"}
set_c = set_a.union(set_b_)
print(set3)

Set intersection (∩) uses the intersection() method.

set_a = {"a", "b", "c"}
set_b = {"b", "c", "d"}
set_c = set_a.intersection(set_b_)
print(set3)

Set difference (\) uses the difference() method.

set_a = {"a", "b", "c"}
set_b = {"b", "c", "d"}
set_c = set_a.difference(set_b_)
print(set3)

Questions

1. Check your understanding

Calculate the following, e,g,

  Expression Answer
0. { }
1. Union
  Expression Answer  
1. { }
2. { }
3. { }
4. { }

Check Answers

2. Intersection
  Expression Answer  
1. { }
2. { }
3. { }
4. { }

Check Answers

3. Difference
  Expression Answer  
1. { }
2. { }
3. { }
4. { }

Check Answers

Summary

In this section we have learned about the operations you can perform on sets. Now you can move on to the set theory challenges.