Get a random unique element from an Array until all elements have been picked in Swift

Question

I have the following array:

var notebookCovers = [\"cover1\", \"cover2\", \"cover3\", \"cover4\", \"cover4\", \"cover6\", \"cover7\", \"cover8\", \"cover9\"         


        

Answer 1

Copy the array. Shuffle the copy. Now just keep removing the first element until the copy is empty. When it is empty, start over.

Example:

let arr = [1,2,3,4,5]
var copy = [Int]()
for _ in 1...30 { // just to demonstrate what happens
    if copy.isEmpty { copy = arr; copy.shuffle() }
    let element = copy.removeFirst() ; print(element, terminator:" ")
}
// 4 2 3 5 1 1 5 3 2 4 4 1 2 3 5 1 4 5 2 3 3 5 4 2 1 3 2 4 5 1