Immutability: Only immutable types can be hashed because their hash value must remain constant throughout their lifetime.
Uniqueness: While the hash function aims to return a unique hash value for each unique value, it is possible for two different values to have the same hash value, a situation known as a hash collision.
Use in Data Structures: Hash values are integral to the efficiency of Python data structures like sets and dictionaries, allowing for quick data access.
Limitations of hash() Function
While the hash() function is powerful, it has limitations, particularly the potential for hash collisions. Additionally, the specific hash values for objects are not guaranteed to be the same across different versions of Python or even different executions of the same program. Therefore, hash values should not be used for cryptographic purposes or persisted for long-term storage.