How to recover the first letter of a Swift array

Question

I would like to know how to retrieve the first letter of an array element

var wordEasy = ["uva", "manga"]

var teste: String = wordEasy[0]

I would like to retrieve only the letter u

Answer 1

You can use this extension

extension String {

  subscript (i: Int) -> Character {
    return self[self.startIndex.advancedBy(i)]
  }

  subscript (i: Int) -> String {
    return String(self[i] as Character)
  }

  subscript (r: Range<Int>) -> String {
    let start = startIndex.advancedBy(r.startIndex)
    let end = start.advancedBy(r.endIndex - r.startIndex)
    return self[Range(start: start, end: end)]
  }
}

The result:

"abcde"[0] === "a"
"abcde"[0...2] === "abc"
"abcde"[2..<4] === "cd"

Credits: https://stackoverflow.com/questions/24092884/get-nth-character-of-a-string-in-swift-programming-language

Answer 2

If you do not want to use the extension suggested in Jeferson’s answer, use the same method as her:

var wordEasy = ["uva", "manga"]
var teste: String = wordEasy[0]
let u = teste[teste.startIndex]
print(u)

Worth a look at Apple’s official reference on strings on Swift.

Answer 3

You can extend the Array type using where clause to extend only elements that can be converted to String. Create a property to return an array of Strings. Use map to convert each element to String, extract the first element of the character array using the prefix(n) property of the characters and convert the Character to String before returning it.

extension Array where Element: StringLiteralConvertible {
    var initials: [String] {
        return map{String(String($0).characters.prefix(1))}
    }
}

Testing:

let frutas = ["uva", "manga"]

let frutasInitials = frutas.initials   // ["u","m"]