O'Reilly logo

Mastering Swift by Jon Hoffman

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Dictionaries

While dictionaries are not as commonly used as arrays, they have an additional functionality that makes them incredibly powerful. A dictionary is a container that stores multiple key-value pairs, where all the keys are of the same type, and all the values are of the same type. The key is used as a unique identifier for the value. A dictionary does not guarantee the order in which the key-value pairs are stored since we look up the values by the key, rather than by the index of the value.

Dictionaries are good for storing items that map to unique identifiers, where the unique identifier should be used to retrieve the item. As an example, countries with their abbreviations are a good example of items that can be stored in a dictionary. ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required