What type of data structure is a dictionary in Python?

A dictionary in Python is classified as an unordered collection of items. This means that the elements within a dictionary are stored without a specific sequence, and there is no inherent ordering associated with the keys or values. Each item in a dictionary consists of a key-value pair, allowing for efficient retrieval of values based on their keys.

Unlike a sequence, which is typically an ordered collection (like a list or tuple), dictionaries do not maintain the order of items based on their positions. Instead, accessing items relies on the uniqueness of the keys. When a dictionary is created or modified, the arrangement of the key-value pairs can change, yet the association between the keys and their corresponding values remains intact.

This characteristic of being unordered allows dictionaries to facilitate quick lookups, making them particularly useful for scenarios where search speed is essential. Understanding this property helps in leveraging dictionaries effectively in Python programming, ensuring proper selection of data structures based on the requirements of a given task.