What is a hash table, how is it represented in Python, and what are its operation complexities?

A hash table is a data structure that stores key-value pairs and provides fast access to values by key in amortized O(1) time.

In Python, the hash table is implemented through the built-in data type dict. It uses a hash function to compute an index in an array where the value is stored.

Average operation complexities:

• Insertion: O(1)
• Search: O(1)
• Deletion: O(1)

In the worst case (with collisions), the complexity can degrade to O(n), but thanks to good hashing and dynamic resizing of the table, this rarely happens.

Example usage:

my_dict = {'apple': 1, 'banana': 2}
print(my_dict['apple'])  # 1
my_dict['orange'] = 3