How are sets and dictionaries implemented in Python?

Sets in Python are implemented based on hash tables. They are unordered collections of unique elements. Elements must be hashable (i.e., immutable).

Dictionaries are also implemented based on hash tables. They store key-value pairs, where keys must be unique and hashable. Search, insertion, and deletion of elements have an average complexity of O(1).

Advantages of using hash tables:

• Fast access to elements by their hash.
• Efficient memory management due to dynamic resizing of the table.

Possible disadvantages:

• Hash collisions, requiring additional resolution mechanisms (e.g., open addressing or chaining).
• Unordered elements in the standard implementation (modern versions use a different internal structure to preserve order).

# Example of creating a set
my_set = {1, 2, 3, 1} # Duplicates are ignored

# Example of creating a dictionary
my_dict = {"a": 1, "b": 2}

In modern Python versions (starting from 3.7 for standard dictionaries), insertion order is preserved thanks to changes in the internal hash table structure, but the principles of hashing remain key.