set(methods)

Question 1

A Python Set

Answer 1

An unordered collection of unique elements. It automatically removes duplicates.

Question 2

How to create an empty set in Python

Answer 2

Use set() - not {} which creates a dictionary.

Question 3

Method to add a single element to a set

Answer 3

.add(element)

Question 4

Method to remove an element, which raises an error if the element isn’t there

Answer 4

.remove(element)

Question 5

Method to remove an element, which does nothing if the element isn’t there (safer)

Answer 5

.discard(element)

Question 6

Operation to find all elements in either of two sets (A or B)

Answer 6

Union (set1 | set2 or set1.union(set2))

Question 7

Operation to find elements common to both of two sets (A and B)

Answer 7

Intersection (set1 & set2 or set1.intersection(set2))

Question 8

Operation to find elements in the first set but not in the second (A minus B)

Answer 8

Difference (set1 - set2 or set1.difference(set2))

Question 9

Operation to find elements in either set, but not in both (A XOR B)

Answer 9

Symmetric Difference (set1 ^ set2 or set1.symmetric_difference(set2))

Question 10

What is the main advantage of using a set over a list for checking if an item exists?

Answer 10

Speed (membership testing is very fast, O(1), in sets)