Working with Sets in Swift

Sets in Swift are unordered collections of unique elements. They are very useful when working with data that needs to be distinct and ordering doesn't matter. Unlike arrays, you cannot access elements in a set using an index. Let's take a look at how we can create and work with sets in Swift.

Creating Sets

We can create an empty set in Swift using the following syntax.

var someSet = Set()}

We can also use an array literal to create a set with initial values.

var favoriteNumbers: Set = [3, 7, 22, 16, 7]}

Note that the Set initializer removes duplicates, so the resulting set will only contain unique values.

Working with Sets

We can add elements to a set using the `insert()` method.

favoriteNumbers.insert(42)}

We can also remove elements using the `remove()` method.

favoriteNumbers.remove(7)}

To check if a set contains a particular element, we can use the `contains()` method.

if favoriteNumbers.contains(22) {
    print("My favorite number is 22!")
}

We can also perform set operations such as union, intersection and subtraction between two sets. Let's take a look at how we can do this.

Set Operations

Union: The union of two sets is a new set that contains all the elements from both sets. We can find the union of two sets using the `union()` method.

let myFavoriteNumbers: Set = [3, 7, 22]
let myWifesFavoriteNumbers: Set = [16, 7, 42, 22]

let ourFavoriteNumbers = myFavoriteNumbers.union(myWifesFavoriteNumbers)}

Intersection: The intersection of two sets is a new set that contains all the elements that are common in both sets. We can find the intersection of two sets using the `intersection()` method.

let commonFavoriteNumbers = myFavoriteNumbers.intersection(myWifesFavoriteNumbers)}

Subtraction: The subtraction of one set from another is a new set that contains all the elements from the first set that are not in the second set. We can subtract one set from another using the `subtracting()` method.

let myNonOverlappingFavoriteNumbers = myFavoriteNumbers.subtracting(myWifesFavoriteNumbers)}

Conclusion

Sets are an extremely useful tool in Swift which allows us to work with collections of unique elements in an efficient manner. They also provide access to useful set operations for solving various programming problems.