swift dictionary change order of elements automatically [Swift]

Question

In my swift app I've the following function:

func generateTimetable() -> [String:String] {

    var dayCellTFText = [String]()

    for i in 1...7 {
        let cell = tableView.cellForRow(at: [0,i]) as! DayCell
        dayCellTFText.append(cell.timetableTextField.text!)
    }

    let timetable = ["monday":dayCellTFText[0],"thuesday":dayCellTFText[1],"wednesday":dayCellTFText[2],"thursday":dayCellTFText[3],"friday":dayCellTFText[4],"saturday":dayCellTFText[5],"sunday":dayCellTFText[6]]
    return timetable
}

When I invoke the function by, for example, print(generateTimetable()) This is the output:

["thuesday": "", "wednesday": "", "saturday": "", "thursday": "", "monday": "", "friday": "", "sunday": ""]

The problem is that the dictionary's elements changed positions! How can I solve this?

A dictionary is a unordered collection. What you need is to sort your dictionary based on its keys keys and use the resulting array of key/value elements. — Leo Dabus, Aug 25 '18 at 12:46
possible duplicate of https://stackoverflow.com/questions/31527754/sort-dictionary-by-key-value/31528848#31528848 — Leo Dabus, Aug 25 '18 at 12:48

ielyamani · Accepted Answer · 2018-08-25T13:56:03.623

Using a [String : String] is the wrong choice for the return value of the generateTimetable(). If you want an ordered collection you should use arrays. The question is what would be the type contained by the array? Here are two possible solutions:

A tuple :

func generateTimetable() -> [(String,String)] {

    var dayCellTFText = [String]()

    for i in 1...7 {
        let cell = tableView.cellForRow(at: [0,i]) as! DayCell
        dayCellTFText.append(cell.timetableTextField.text!)
    }

    let timetable = [("monday",dayCellTFText[0]),
                     ("tuesday",dayCellTFText[1]),
                     ("wednesday",dayCellTFText[2]),
                     ("thursday",dayCellTFText[3]),
                     ("friday",dayCellTFText[4]),
                     ("saturday",dayCellTFText[5]),
                     ("sunday",dayCellTFText[6])]
    return timetable
}

A struct

struct TableEntry {
    let nameOfDay: String
    let textFieldtext: String
}

func generateTimetable() -> [TableEntry] {

    var dayCellTFText = [String]()

    for i in 1...7 {
        let cell = tableView.cellForRow(at: [0,i]) as! DayCell
       dayCellTFText.append(cell.timetableTextField.text!)
    }

    let timetable = [ TableEntry(nameOfDay: "monday", textFieldtext: dayCellTFText[0]),
                      TableEntry(nameOfDay: "tuesday", textFieldtext: dayCellTFText[0]),
                      TableEntry(nameOfDay: "wednesday", textFieldtext: dayCellTFText[0]),
                      TableEntry(nameOfDay: "thursday", textFieldtext: dayCellTFText[0]),
                      TableEntry(nameOfDay: "friday", textFieldtext: dayCellTFText[0]),
                      TableEntry(nameOfDay: "saturday", textFieldtext: dayCellTFText[0]),
                      TableEntry(nameOfDay: "sunday", textFieldtext: dayCellTFText[0]),
                      TableEntry(nameOfDay: "monday", textFieldtext: dayCellTFText[0])]
    return timetable
}

And thus the return type will be inherently ordered. If you are still interested in sorting a dictionary by its keys, here is an already answered question. But that supposes that the keys already have numerical or alphabetical order (or any sorting order for that matter). But the string "monday", "tuesday", ..., "sunday" are not alphabetically ordered.

swift dictionary change order of elements automatically [Swift]

1 Answers1