Get nth character of a string in Swift programming language

Question

How can I get the nth character of a string? I tried bracket([]) accessor with no luck.

var string = \"Hello, world!\"

var firstChar = string[         


        

Answer 1

Xcode 11 • Swift 5.1

You can extend StringProtocol to make the subscript available also to the substrings:

extension StringProtocol {
    subscript(_ offset: Int)                     -> Element     { self[index(startIndex, offsetBy: offset)] }
    subscript(_ range: Range)               -> SubSequence { prefix(range.lowerBound+range.count).suffix(range.count) }
    subscript(_ range: ClosedRange)         -> SubSequence { prefix(range.lowerBound+range.count).suffix(range.count) }
    subscript(_ range: PartialRangeThrough) -> SubSequence { prefix(range.upperBound.advanced(by: 1)) }
    subscript(_ range: PartialRangeUpTo)    -> SubSequence { prefix(range.upperBound) }
    subscript(_ range: PartialRangeFrom)    -> SubSequence { suffix(Swift.max(0, count-range.lowerBound)) }
}

---

extension LosslessStringConvertible {
    var string: String { .init(self) }
}

---

extension BidirectionalCollection {
    subscript(safe offset: Int) -> Element? {
        guard !isEmpty, let i = index(startIndex, offsetBy: offset, limitedBy: index(before: endIndex)) else { return nil }
        return self[i]
    }
}

---

Testing

let test = "Hello USA