How to find an item in an array using firstIndex(of:)

Swift version: 5.0

Paul Hudson    @twostraws    May 28th 2019

The firstIndex(of:) method tells you the index of an element in an array if it exists, or returns nil otherwise. Because it's an optional value, you need to unwrap it carefully or at least check the result, like this:

let array = ["Apples", "Peaches", "Plums"]

if let index = array.firstIndex(of: "Peaches") {
    print("Found peaches at index \(index)")
}

Note: in earlier versions of Swift this method was called index(of:).

Available from iOS 7.0

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