how to change the subscript in an array of arrays

Question

I want to change subscript coordinates in an Array of Arrays [[Int]] in order to be able to address each value in a way similar to a spreadsheet, so assigning values, formulas across cells, etc.

Currently to address each value I need to subscript like table[2][1] = 12 or similar. I would like to subscript like a spreadsheet table[a][2] = 12, so that I can adapt long and complicated formulas in bigger speadsheets to similar tables using the same system used in spreadsheets.

The question is: how to change the subscript system in an efficient way? I send a simplified example to ilustrate the point

class ViewController: UIViewController {

var table = [[0,  1,  2,  3],
             [1, 32, 44, 25],
             [2, 12, 66, 43],
             [3,  3,  4,  5]]


override func viewDidLoad() {
    super.viewDidLoad()

    print(table[2][1])  // 12
    table[1][1] = 100
    table[3][3] = table[1][1] * table[3][1] * 10
    print(table[3][3])

    printArray(table: table, j: 3)


}

// MARK: - Function

func printArray(table: [[Int]], j:Int) {
    for i in 0...j {
        print(table[i])
    }
}

}

This is the most efficient way. What you are asking for is how to make it easily understandable for viewing so that you can compare it with a spreadsheet grid. I wouldn't recommend changing your code to suit viewing needs. Also, I'm curious to know where you would be using hardcoded subscripts. — Rakesha Shastri
– Rakesha Shastri, Commented Oct 22, 2018 at 9:07
I see your point but there are many, long and complicated excel formulas to be translated, with IFs and other formulas concatenated, so I need to adapt them easily and without errors to my IOS, so a tool to change subscript would help a lot — Fausto Checa
– Fausto Checa, Commented Oct 22, 2018 at 9:12
For example of formula: =SI(Y($Y$17>1;AA9>0;$H$10<=Tablas!$C$9);"NORMAL";SI(Y($Y$17>1;AA9>0;$H$10>Tablas!$C$9;$H$10<=Tablas!$C$10);"SUPERADA";SI(Y($Y$17>1;AA9>0;$H$10>Tablas!$C$10);"ROTURA";"N/A"))) — Fausto Checa
– Fausto Checa, Commented Oct 22, 2018 at 9:22
You can use dictionary with letter keys and array values instead of array of arrays. — Mojtaba Hosseini
– Mojtaba Hosseini, Commented Oct 22, 2018 at 9:26
Why not create a wrapper class/struct containing your array of arrays as the data source and with different functions that accepts cell coordinates in a format you want like (‘C’, 9) or (‘$C$9’) etc — Joakim Danielson
– Joakim Danielson, Commented Oct 22, 2018 at 9:47

Andreas Oetjen · Accepted Answer · 2018-10-22 19:20:34Z

2

The closest solution I found is to use enums, like here:

enum Column:Int {
    case a
    case b
    case c 
    // and so on
}

extension Array {
    subscript(col:Column) -> Element {
        get {
            return self[col.rawValue]
        }
        set(newValue) {
            self[col.rawValue] = newValue
        }
    }
}


var table = [[0,  1,  2,  3],
            [1, 32, 44, 25],
            [2, 12, 66, 43],
            [3,  3,  4,  5]]


table[.a][2] = 12
let val = table[.a][2]
print (val)

Nevertheless, there are two little drawbacks:

you first have hard-code all the "column" letters you want to access to the Column enum.
then, something like table[5][.c] and table[.a][.b] will also be allowed - so you could access the rows via letter, not only the columns

edited Oct 22, 2018 at 19:20

answered Oct 22, 2018 at 11:48

Andreas Oetjen

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4 Comments

Fausto Checa Over a year ago

Andreas I see a major problem, your solution is table[row] [column], but I need table [column] [row] the same as in Excel

Andreas Oetjen Over a year ago

So, with the first subscript you want to access the "inner" array, and with the second the "outer"?

Fausto Checa Over a year ago

what i mean is: Table > I would paste it from Excel in the matrix var table of IOS, very convenient. So columns and rows as indicated in my example. Formulas > I need Table [column][row] like in excel so to copy the formulas with the same subscripts

Fausto Checa Over a year ago

=SI(Y($Y$17>1;AA9>0;$H$10<=Tablas!$C$9);"NORMAL";SI(Y($Y$17>1;AA9>0;$H$10>Tablas!$C$9;$H$10<=Tablas!$C$10);"SUPERADA";SI(Y($Y$17>1;AA9>0;$H$10>Tablas!$C$10);"ROTURA";"N/A")))

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