What are lists in Swift, and how can I use subscripts with a list?

Question

The Swift Programming Guide (Swift 5.1 Edition) says that subscripts can be used to access members of “a collection, list, or sequence.” Collection and Sequence are defined protocols in Swift and are well documented. Do lists exist in Swift as a separate entity? If so, what is the syntax for a list subscript?

Would someone care to explain the downvotes? – Mark Cowan Sep 22 '19 at 10:26 — Mark Cowan, Sep 22 '19 at 10:26

score 1 · Accepted Answer · answered Sep 22 '19 at 05:08

1

It would be better if The Swift Programming Language (the book) didn't say “ a collection, list, or sequence”. As you point out, Swift has standard Collection and Sequence types. It does not have any standard type named List.

The closest thing would be Array:

let words: Array<String> = ["Mark", "Cowan"]
// or words: [String]
let firstWord = words[0]

answered Sep 22 '19 at 05:08

rob mayoff

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Thanks, @rob, but an array is both a collection and a sequence. How is a list different? Or is the passage I quoted simply misleading? – Mark Cowan Sep 22 '19 at 12:48
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`Collection` inherits `Sequence`, so every type that conforms to `Collection` also conforms to `Sequence`. There is no type or protocol named `List` in the standard library, so the passage is misleading. – rob mayoff Sep 22 '19 at 16:49

What are lists in Swift, and how can I use subscripts with a list?

1 Answers1