How to check if an element is in an array

Question

In Swift, how can I check if an element exists in an array? Xcode does not have any suggestions for contain, include, or has, and a qu

Answer 1

what about using a hash table for the job, like this?

first, creating a "hash map" generic function, extending the Sequence protocol.

extension Sequence where Element: Hashable {

    func hashMap() -> [Element: Int] {
        var dict: [Element: Int] = [:]
        for (i, value) in self.enumerated() {
            dict[value] = i
        }
        return dict
    }
}

This extension will work as long as the items in the array conform to Hashable, like integers or strings, here is the usage...

let numbers = Array(0...50) 
let hashMappedNumbers = numbers.hashMap()

let numToDetect = 35

let indexOfnumToDetect = hashMappedNumbers[numToDetect] // returns the index of the item and if all the elements in the array are different, it will work to get the index of the object!

print(indexOfnumToDetect) // prints 35

But for now, let's just focus in check if the element is in the array.

let numExists = indexOfnumToDetect != nil // if the key does not exist 
means the number is not contained in the collection.

print(numExists) // prints true