How to add element at Last index Swift - ios

Question

I am getting an Array from server and I store it in NSMutableArray. Now the issue is that the Array is not sorted. For eg. array = ["A","B","None","C","D"]. I want to sort it and place the "None" element at last. i.e ["A","B","C","D","None"]. Tried swapping but was unable to match the condition, as the array may increase in future. Check my code below which is not working as expected.
if array.containsObject( "None" ){
print("\(array.indexOfObject("None"))")
let noneIndex = array.indexOfObject("None")
print(noneIndex)
array.removeObject(noneIndex)
print("Remove Array:-\(array)")
array.insertObject(noneIndex, atIndex: (array.lastObject?.index)!)
print("Sorted Array:-\(array)")
}

Answer 1

Maybe I'm misunderstanding what it is that you need to do, but you could use sorted() on your array if you just want to sort it alphabetically.
You could also use filter to remove "None" from your array, sort it, and then append "None" as the last element
For instance, if you have
let elements = ["Alpha", "Bold", "None", "charlie", "Delta", "echo", "zebra", "k"]
You could start out by filtering it:
let filteredElements = elements.filter { $0.uppercased() != "NONE"}
Sort the filtered elements:
var sortedElements = filteredElements.sorted { $0.uppercased() < $1.uppercased()}
Append "None"
sortedElements.append("None") // ["Alpha", "Bold", "charlie", "Delta", "echo", "k", "zebra", "None"]
And be done.
Here it is combined:
let lastElement = "None"
let elements = ["Alpha", "Bold", "None", "charlie", "Delta", "echo", "zebra", "k"]
var sortedElements = elements.filter({$0.uppercased() != lastElement.uppercased()}).sorted(by: {$0.uppercased() < $1.uppercased()})
sortedElements.append(lastElement)
Hope that helps you.

Answer 2

var array = ["A", "B", "None", "C", "D"]
if let noneIndex = array.index(of: "None") {
array.remove(at: noneIndex)
array.append("None")
}
print(array)

Answer 3

This should move None at the end of the array, and sort the other elements:
let ["A", "B", "None", "C", "D"]
array.sorted { $1 == "None" || $0 < $1 } // ["A", "B", "C", "D", "None"]
This simply takes benefits of the by argument that can be passed to the sort/sorted method from Array.
Edit #MartinR had a very strong point regarding the comparison predicate from this answer, which indeed doesn't offer a strong weak ordering. Sorting the array with a correct predicate would be along the lines of:
array.sorted { $0 == "None" ? false : $1 == "None" ? true : $0 < $1 }

Answer 4

This will work:
// starting test array
let array = ["B", "None", "C","P","None","A", "Q"]
var sorted = array.sorted { (str1, str2) -> Bool in
return str1 < str2
}
sorted.forEach { str in
if str == "None" {
if let idx = sorted.index(of: str) {
sorted.remove(at: idx)
sorted.append(str)
}
}
}
// Sorted array is now ["A", "B", "C", "P", "Q", "None", "None"]