Create a team generator with a given number of teams - ios

Question

I would like to take an array of [String] and split it up into a given number of groups.
I have tried using this extension
extension Array {
func chunked(into size: Int) -> [[Element]] {
return stride(from: 0, to:count, by: size).map {
Array(self[$0 ..< Swift.min($0 + size, count)])
}
}
}
to split the array into a given number of elements per subarray, which for that function it works.
But to split it into a desired number of subarrays, I tried dividing the array.count by the desired number of teams, which works but only in certain circumstances.
If there are any extra elements, it puts them into an extra subarray at the end, and the number needs to come out even if I want this to work perfectly, which is the minority of the time.
So I guess this array.chunked function is not the solution in any way.
Maybe there is a way to do it with a for loop by taking an array.randomElement(), adding that to a variable (which would be a team) and then removing that element from the original array, and iterating over it until the original array is empty. And end up with an array of subarrays which would be the teams, or just separate variables which would be the teams. It could be any of those options.
Any ideas on how to do this?

Answer 1

Think about how you deal cards.
If you have 7 players, you start with one player and go around, giving one card at a time to each player. At the end, you may run out of cards before giving everybody the same number of cards. Some people may have n cards, and some may have n-1. That's the best that you can do.
You could implement the same thing with a source array and your destination arrays. Remove one element at a time from the source array, and "round-robbin" add it to one of the destination arrays until the source array is exhausted.
That code might look like this:
func splitArray<T>(array: [T], subArrayCount: Int) -> [[T]] {
// Create an empty array of arrays
var result = [[T]]()
// Create the empty inner string arrays
for _ in 1...subArrayCount {
let innerArray = [T]()
result.append(innerArray)
}
for (index, element) in array.enumerated() {
result[index % subArrayCount].append(element)
}
return result
}
And to test it:
let string = "Now is the time for all good programmers to babble incoherently. The rain in spain falls mainly on the plain. Fourscore and seven years ago our forefathers brought forth to this continent a new nation conceived in liberty and dedicated to the cause that all men are created equal."
let array = string.split(separator: " ")
.map { String($0) }
let subArrays: [[String]] = splitArray(array: array, subArrayCount: 5)
for (index, array) in subArrays.enumerated() {
let countString = String(format: "%2d", array.count)
print ("Array[\(index)]. Count = \(countString). Contents = \(array)")
}
The output of that test is:
Array[0]. Count = 10. Contents = ["Now", "all", "incoherently.", "falls", "Fourscore", "our", "this", "conceived", "to", "men"]
Array[1]. Count = 10. Contents = ["is", "good", "The", "mainly", "and", "forefathers", "continent", "in", "the", "are"]
Array[2]. Count = 10. Contents = ["the", "programmers", "rain", "on", "seven", "brought", "a", "liberty", "cause", "created"]
Array[3]. Count = 10. Contents = ["time", "to", "in", "the", "years", "forth", "new", "and", "that", "equal."]
Array[4]. Count = 9. Contents = ["for", "babble", "spain", "plain.", "ago", "to", "nation", "dedicated", "all"]