I made this work in Swift by overloading the operator

var n = Int(readLine()!)!

func *(string: String, scalar:Int) -> String {
    let value = Array(count: scalar, repeatedValue: string)
    return value.joinWithSeparator("")
}

for i in 1..<n + 1 {
    print(" " * (n - i) + "#" * i)
}

https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/AdvancedOperators.html