What is a unique feature of a Map or Dictionary?

A dictionary, or map, is a data structure that stores data in key-value pairs. A unique feature of this structure is that the keys must be unique. This means each key corresponds to exactly one value, and no two keys can be the same within a single dictionary. This uniqueness of keys allows for efficient retrieval, as the data can be accessed quickly using the specified key without confusion.

In contrast, the other options do not accurately represent the defining characteristics of dictionaries. For example, while removing duplicates might be a property of certain data structures, maps inherently do not allow duplicate keys, which is different from merely stating they do not allow duplicates in a broader sense. Not all values in a dictionary are required to be integers; they can be of any datatype, including strings, lists, or other dictionaries. Lastly, the items in a dictionary are not ordered in the traditional sense found in lists; dictionaries maintain insertion order as of Python 3.7 but do not inherently provide ordering in the same way as sequences do. Therefore, the uniqueness of keys is what truly distinguishes maps and dictionaries as a data structure.