Delete item in array, inside another array in Swift

Question

I've got a An array which is a an array of Sections in the Table View. I have got another array that contain arrays in it. I displayed it on the table view correctly, but each time I want to delete it, I get an error. I want to delete the exactly item in the array which is inside the array. Here is what I got so far:

        class ViewController: UIViewController, UITableViewDelegate {

        @IBOutlet var tableView: UITableView!
        var eachSection = ["a","ss","dd","heyyyyyy","3"]
        var eachStep = [["z","zz"],["x","xx"],["c","cc","ccc"],["r","rr","rrr","rrrr"],["o"]]

        func numberOfSectionsInTableView(tableView: UITableView) -> Int {
            return eachSection.count
        }

        func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
            let sectionString = Array(eachStep)[section]

            return sectionString.count
        }

        func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
            let cell = tableView.dequeueReusableCellWithIdentifier("cell", forIndexPath: indexPath)

            // Configure the cell...
            let sectionString = Array(eachStep)[indexPath.section]
            cell.textLabel?.text = sectionString[indexPath.row]
            print(sectionString)
            return cell
        }

        func tableView(tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
            let sectionString = eachSection[section]
            return sectionString
        }

        func tableView(tableView: UITableView, commitEditingStyle editingStyle: UITableViewCellEditingStyle, forRowAtIndexPath indexPath: NSIndexPath) {
            let cell = tableView.dequeueReusableCellWithIdentifier("cell", forIndexPath: indexPath)
            if (editingStyle == UITableViewCellEditingStyle.Delete) {
                var sectionString = Array(eachStep)[indexPath.section]
                sectionString.removeAtIndex(indexPath.row)
                tableView.deleteRowsAtIndexPaths([indexPath], withRowAnimation: UITableViewRowAnimation.Automatic)
            }
        }
}

This is the error I got:

Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Invalid update: invalid number of rows in section 0. The number of rows contained in an existing section after the update (2) must be equal to the number of rows contained in that section before the update (2), plus or minus the number of rows inserted or deleted from that section (0 inserted, 1 deleted) and plus or minus the number of rows moved into or out of that section (0 moved in, 0 moved out)

is your array is mutable ? and are the data in the array from websrvice response(json formated data) ? — sourav
– sourav, Commented Mar 25, 2016 at 11:48
@OlegGordiichuk Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Invalid update: invalid number of rows in section 0. The number of rows contained in an existing section after the update (2) must be equal to the number of rows contained in that section before the update (2), plus or minus the number of rows inserted or deleted from that section (0 inserted, 1 deleted) and plus or minus the number of rows moved into or out of that section (0 moved in, 0 moved out). — Eliko
– Eliko, Commented Mar 25, 2016 at 11:50
Hello. Please don't post error messages or code in the comments (it's not readable and comments can be deleted at any time). You should edit your question instead. Thank you! — Eric Aya
– Eric Aya, Commented Mar 25, 2016 at 11:54

Oleg Gordiichuk · Accepted Answer · 2016-03-25 12:08:01Z

2

This error contains answer for youre question.

Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Invalid update: invalid number of rows in section 0. The number of rows contained in an existing section after the update (2) must be equal to the number of rows contained in that section before the update (2), plus or minus the number of rows inserted or deleted from that section (0 inserted, 1 deleted) and plus or minus the number of rows moved into or out of that section (0 moved in, 0 moved out).

Look carefully what are you doing.

You delete items from one array that you are not using as data source.

 var sectionString = Array(eachStep)[indexPath.section]
 sectionString.removeAtIndex(indexPath.row)

Try this:

eachStep[indexPath.section].removeAtIndex(indexPath.row)

edited Mar 25, 2016 at 12:08

answered Mar 25, 2016 at 11:54

Oleg Gordiichuk

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3 Comments

Eliko Over a year ago

Yea, this is the error, But how I correct it and why? I understand my mistake now but I don't know how to correct it

Lou Franco Over a year ago

sectionString is a copy of the array inside eachStep. You need to do something like eachStep[indexPath.section] = sectionString to copy it back.

Oleg Gordiichuk Over a year ago

Your datasource was always full because you delete items from the copy of your datasource.

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