How to group arrays using dictionaries
Swift version: 5.0
If you have an array of items and want to group them according to some criteria, Swift has a special dictionary initializer just for you.
Here’s an example sequence we can work with:
let singers = ["Ed Sheeran", "Ariana Grande", "Taylor Swift", "Adele Adkins"]We can now create a dictionary that groups those singers together by the length of their names:
let groupedByLength = Dictionary(grouping: singers) { $0.count }That will put Taylor and Adele into an array under the “12” key, Ariana under 13, and Ed under 10.
Alternatively, we could group them by the first letters of each of their names:
let groupedByFirst = Dictionary(grouping: singers) { $0.first! }SPONSOR Tired of wasting time debugging your Swift app? Instabug’s SDK is here to help you minimize your debugging time by providing you with complete device details, network logs, and reproduction steps with every bug report. All data is attached automatically. It only takes a line of code to setup. Get started for free.
Available from iOS 8.0 – learn more in my book Pro Swift
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