How to make alphabetically section headers in table view with a mutable data source

Question

I store strings of a view controller in a string array. I import this string array as a Data Source in my table view. This all works smoothly. But now I would like to sort t

Answer 1

For Swift 3. Thank you @Stefan! Here is my version with Set

var tableViewSource: [Character : [String]]!
var tableViewHeaders: [Character]!

let data = ["Anton", "Anna", "John", "Caesar"]

func createTableData(wordList: [String]) -> (firstSymbols: [Character], source: [Character : [String]]) {

    // Build Character Set
    var firstSymbols = Set()

    func getFirstSymbol(word: String) -> Character {
        return word[word.startIndex]
    }

    wordList.forEach {_ = firstSymbols.insert(getFirstSymbol(word: $0)) }

    // Build tableSourse array
    var tableViewSourse = [Character : [String]]()

    for symbol in firstSymbols {

        var words = [String]()

        for word in wordList {
            if symbol == getFirstSymbol(word: word) {
                words.append(word)
            }
        }

        tableViewSourse[symbol] = words.sorted(by: {$0 < $1})
    }

    let sortedSymbols = firstSymbols.sorted(by: {$0 < $1})

    return (sortedSymbols, tableViewSourse)
}

func getTableData(words: [String]) {
    tableViewSource = createTableData(wordList: words).source
    tableViewHeaders = createTableData(wordList: words).firstSymbols
}

getTableData(words: data)

print(tableViewSource)  // ["J": ["John"], "C": ["Caesar"], "A": ["Anna", "Anton"]]
print(tableViewHeaders) // ["A", "C", "J"]