On Feb 26, 2021, at 2:24 PM, David Koontz <david@...> wrote:

Help an old timer out... I don't know why this does NOT work...

I want to redefine the subscript method... in Swift ...?

var str = "Hello, playground"

?

//

// Extensions can add new subscripts to an existing type.

?

class Inning {

?? ? var array = ["first", "second", "third", "fourth", "fifth", "sixth", "seventh", "eighth", "ninth"]

}

?

let inning = Inning()

?

print ("\(inning.array[1]) inning")

// prints "second inning"

?

extension Array {

? ? subscript(digitIndex: Int) -> Int {

? ? ? ? let decimalBase = 1

? ? ? ? return digitIndex - decimalBase

? ? }

}

?

//print("\(Inning[1]) inning")

let x = inning.array[1]

?

print ("\(x) inning") ? ? // expect first inning via use of extension

Much like the document does here:
Subscripts

Extensions can add new subscripts to an existing type. This example adds an integer subscript to Swift’s built-in?Int?type. This subscript?[n]?returns the decimal digit?n?places in from the right of the number:

• 123456789[0]?returns?9
• 123456789[1]?returns?8

…and so on:

1. extension Int {
2. subscript(digitIndex: Int) -> Int {
3. var decimalBase = 1
4. for _ in 0..<digitIndex {
5. decimalBase *= 10
6. }
7. return (self / decimalBase) % 10
8. }
9. }
10. 746381295[0]
11. // returns 5
12. 746381295[1]
13. // returns 9
14. 746381295[2]
15. // returns 2
16. 746381295[8]
17. // returns 7