What is indexPath in NSIndexPath

Question

I have this trunk of code

func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {

    let cell = UITableViewCell(style: UITableViewCellStyle.Default, reuseIdentifier: "Cell")

    cell.textLabel?.text = toDoList[indexPath.row] //will give us the 0th, 1st, 2nd etc..

    return cell

can somebody explain to me what is the "indexPath" in the first line?

Answer 1

indexPath is the local name of the parameter whose external name is cellForRowAtIndexPath.

indexPath is defined inside the function body (and you do use it), while the function caller has to use cellForRowAtIndexPath when they name the function parameter: let cell = tableView.delegate.tableView(tableView, cellForRowAtIndexPath: ...)

Compare:

func sum1(a: Int, b: Int) -> Int {
    return a + b
}

func sum2(a: Int, _ b: Int) -> Int {
    return a + b
}

func sum3(integer a: Int, secondInteger b:Int) -> Int {
    return a + b
}

sum1(1, b: 2)
sum2(1, 2)
sum3(integer: 1, secondInteger: 2)

It is time for you to check Apple documentation about Function Parameter Names: https://developer.apple.com/library/prerelease/ios/documentation/Swift/Conceptual/Swift_Programming_Language/Functions.html

Answer 2

NSIndexPath is a sub class of NSObject. It represents the path to specific node in a tree of an array collection.

it has clearly mentioned in here. read this

Your question is based on tableView. you have a collection of cells in a table view. So the node is the cell which you select.

indexPath represents your selected cell in the tree in here.

Answer 3

Visit https://developer.apple.com/library/mac/documentation/Cocoa/Reference/Foundation/Classes/NSIndexPath_Class/

They got a got a good documentation about indexPath.