Swift Sets

Swift Sets

Sets store unique values with no defined order.

Test membership with contains, and use union/intersection operations.

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Deduplicate Values

Use sets to deduplicate values from an array.

Example

var letters: Set<Character> = ["a", "b", "a"]
print(letters.contains("a"))

This example creates a Set which deduplicates values and checks membership.

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Set Operations

Combine or compare sets using union, intersection and subtracting.

Example

let a: Set<Int> = [1, 2, 3]
let b: Set<Int> = [3, 4]
print(a.union(b).sorted())         // [1, 2, 3, 4]
print(a.intersection(b).sorted())  // [3]
print(a.subtracting(b).sorted())   // [1, 2]