Most efficient way of creating a table select view, with headings in swift & IOS

Question

I'd like to have a table view that's used to select a key,value pair. The table will be re-usable for multiple uses, but here's an example using classes and students:

11A/It
4125:John
5121:Ben
6121:Anna
4125:Gemma
10B/It
5121:Ben
6121:Anna
4125:Gemma
4512:Kevin

The class names are the headings - they will not be selectable. The students are selectable, and the table view will pass back both the key and the value, via a protocol.

What is important, is that these all remain in order, which means my first attempt doesn't really work:

var data = [String:[String:String]()
// Causes problems, because dictionaries have no order

So, I thought I could turn the dictionaries into arrays:

var data = [[String:[[String:String]]]()

This allows me to get the number of sections, but then I can't figure out how to get the number of rows:

func numberOfSections(in tableView: UITableView) -> Int {
    return data.count
}
 func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return data[section].first.count // Nope!
}

So, I think I'm looking for a bit of general advice on the best approach. I can see two ways around this:

1. Have an array of headings and data separately, so I can then do something like `data[headings[section]][row]
2. Create a custom key:value type and work with that

I've got a feeling I might be overcomplicating things though - is there a standard accepted way to solve this one. It seems like it must be a pretty common thing to come across? Many thanks in advance!

Answer 1

I would create a struct that can hold your data, rather just an abstract dictionary.

For example

struct ClassData {
    let title: String
    let students: [Student]
}

struct Student {
    id: Int
    name: String
}


let tableData = [ClassData]()

func numberOfSections(in tableView: UITableView) -> Int {
    return tableData.count
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return tableData[section].students.count
}