You have already seen lists that hold values that you can access by using indexes. However, what if you wanted to name each value, instead of using an index? For example, suppose that you want to access a list of cake ingredients, but you do not know where in the array it is. In that case, a dictionary would come in handy.
Dictionaries, sometimes referred to as associative arrays in other languages, are data structures that hold data or information in a key-value order. Dictionaries allow you to access whatever value you want, using the much easier to remember key.
Dictionaries, unlike lists, are indexed using keys, which are usually strings. There are two kinds of dictionaries that you can use in Python: the default dict, which is unordered, and a special kind of dictionary called an OrderedDict. The difference is that the keys in the default dictionary are stored in an unordered manner, whereas an OrderedDict stores key-value pairs in the order of insertion.
A set is a collection...