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Dictionaries

Dictionaries are a different type of structure. Instead of being ordered arrays, they are key-value storage types. Dictionaries do not have any order, per se. Instead, they store everything as key-value pairs. As physical keys, the dictionary's keys have to be unique and unambiguously static. In other words, immutable. Hence, there cannot be two keys of the same value, and lists cannot be used as keys, but tuples can. Frequently, however, keys are strings, as they allow us to add some sort of semantics to the structure:

person = {'name': 'Jim', 'surname': 'Hawkins', 'age':17}

As you can see, dictionaries are defined by the curly brackets, with key-value pairs separated by the colon and split by the comma. Once the dictionary ...