Valid Selected Indicies

validIndicies.swift

struct Datasource {
    
    static let _items = ["Cats", "Dogs", "Crows", "Lions", "Owls", "Hawks", "Fish"]
    
    static let items = Datasource._items + Datasource._items
    
    
    static func validIndiciesForSelectedIndex(index: Int) -> (Int, Int) {
        
        var offset: Int = 0
        
        //it will always be an even number of items in the datasource 
        //since it is _items.count + _items.count so there is no midpoint
        if index > (Datasource.items.count / 2) - 1 {
           
            offset = index - Datasource.items.count / 2
        } else {
            
            offset = index + Datasource.items.count / 2
        }
        
        return (index, offset)
    }
}



//**** Inside your didSelectCell function ******

//indicies of lion
let lionIndicies = Datasource.validIndiciesForSelectedIndex(3) // (3, 10)

//access first element of lionIndicies 
lionIndicies.0 //3

//second element
lionIndicies.1 //10


let currentSelectedIndex = 10 //second lion index, pass this into the validIndiciesFunction

//then check to see that the current selected index is in the tuple
//i think there might be a better way to do this check, but i can't figure one out right now
if (lionIndicies.0 == currentSelectedIndex || lionIndicies.1 == currentSelectedIndex) {
    println("set cell to selected state")
} else {
    println("set cell to deselected state")
}