Hashable Objects in Python Mutable objects are not hashable. You might ask why. Hash function usually depend on object state. So if state changes, the hash function could change, violating the consistency specification. How do you see if something is hashable? Call the hash function on it.

Sets

A Little Math

Stupid Set (You will later write this in Java)

Hashing and Sets Here is why retrieval from a set is fast.

Dictionaries