Appends an element to an array n times

Array.swift

// Tested in Swift 3
mutating func appendN(element: Element, n: Int) {
    guard n > 0 else {
        return
    }

    for _ in 0..<n {
        self.append(element)
    }
}

// Usage
var array = ["Bob", "Steve", "Barry"]
array.appendN(element: "John", n: 2)
// ["Bob", "Steve", "Barry", "John", "John"]