Python data structures: sets

In this video sets are introduced as a non-linear data structure that can be thought of as a bag of unsorted elements where every element appears only once. Sets have various methods such as length, in operation, add, remove, discard, pop, clear, and copy. Sets also support classic operations like subset, superset, union, intersection, and difference. These operations allow for comparing and combining sets to find common or unique elements. The video also covers the importance of remembering that sets are objects, and assigning a set to a new variable creates a reference to the same set, not a copy. Additionally, frozen sets can be used to create immutable sets that cannot be altered.