Dictionaries are another type of data structure that we can use to hold and store information. Dictionaries are built around the idea of storing key-value pairs and they offer a quick solution to look up one piece of information to access another. A key can be any type except a mutable data type. A value has no such restrictions (meaning its type is not restricted). A common key type is the string because in English, we often associate mapping a word or phrase to some longer or extended information. (Read More!)