Appending struct onto Struct Array in Swift 3

Question

I have a Struct:

struct Note{
    var date: String;
    var comment: String;
}

Then I create a an array with two arrays nested within,

var data = [[Note()],[Contributors()]]

These two arrays are used to populate two sections of a Table View. I need to append a struct onto the Notes struct array but when I try and append it using

data[0].append(Note(date: "06-06-2012",comment:"Created Note"))

and

(data[0] as! Note).append(Note(date: "06-06-2012",comment:"Created Note"))

throws the error

Cannot use mutating member on immutable value of type 'Note'

How you can mutate values that need to be casted?

You need to append not a new Note AND Contributors (based on my testing) - data.append([Note(data: "06-06-2012",comment:"Created Note"), [Contributors()]] or something like that — MadProgrammer
– MadProgrammer, Commented May 21, 2018 at 1:02

rmaddy · Accepted Answer · 2018-05-21 01:11:05Z

1

Your initial creation of the arrays is incorrect.

Change:

var data = [[Note()],[Contributors()]]

to:

var data: [Any] = [[Note](),[Contributors]()]

Your code creates an array that contains at index 0 an array of Any that contains one empty Note instance and at index 1 an array of Any that contains one empty Contributors instance.

The fix creates an array that contains an empty Note array at index 0 and an empty Contributors array at index 1.

But even with all of those "fixes", you still get the error if you do:

(data[0] as! Note).append(Note(date: "06-06-2012",comment:"Created Note"))

It's kind of strange to have data contain two different types of data. You really should have two arrays:

var notes = [Note]()
var contributors = [Contributors]()

Then you can easily do:

notes.append(Note(date: "06-06-2012",comment:"Created Note"))

edited May 21, 2018 at 1:11

answered May 21, 2018 at 1:03

rmaddy

319k44 gold badges548 silver badges591 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Abdelahad Darwish · Accepted Answer · 2018-05-21 01:29:48Z

0

You can have solution by using protocol

protocol DataSourceNoteContributors {}

struct Contributors: DataSourceNoteContributors{

}
struct Note:DataSourceNoteContributors{
    var date: String;
    var comment: String;
}

Then can be used easly

    var data = [Note(date: "date", comment: "comment"),Contributors()]

    data.append(Note(date: "note1", comment: "comment2"))
    data.append(Contributors())

// using cast to recognize

if data[0] as Note {

}

answered May 21, 2018 at 1:29

Abdelahad Darwish

6,0771 gold badge19 silver badges35 bronze badges

Collectives™ on Stack Overflow

Appending struct onto Struct Array in Swift 3

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related