C#•2y ago

❔ How to get to one of the arrays in a multidimensional array?

For instance, in:

int[,] array4 = { { 1, 2 }, { 3, 4 }, { 5, 6 }, { 7, 8 } };

int[,] array4 = { { 1, 2 }, { 3, 4 }, { 5, 6 }, { 7, 8 } };

How do I get to just the

{1, 2}

{1, 2}

part?

13 Replies

sibber•2y ago

so you want to get a row

GipperOP•2y ago

yeah

sibber•2y ago

it doesnt look like theres a built in way to do that

jcotton42•2y ago

yeah you can't do that with MD arrays directly you'd have to iterate through it manually using methods like GetLowerBound/GetUpperBound passing the corresponding dimension because it's not an array of arrays it's a truly multidimensional array

GipperOP•2y ago

So do I have to double loop it and put array4[0,j] into another array?

jcotton42•2y ago

you can do this directly with an array of arrays (aka jagged arrays) int[][]

GipperOP•2y ago

oh thanks

jcotton42•2y ago

MD arrays are really awkward to use much of the time they're a neat idea, but don't work that well in practice

Anton•2y ago

No they just have a bad API

MODiX•2y ago

Henkypenky#4865

REPL Result: Failure

#nuget CommunityToolkit.HighPerformance

int[,] array4 = { { 1, 2 }, { 3, 4 }, { 5, 6 }, { 7, 8 } };

var span2D = new Span2D<int>(array4);

var row = span2D.GetRowSpan(0);

foreach (var x in row)
{
    Console.Write($"{x} ");
}

#nuget CommunityToolkit.HighPerformance

int[,] array4 = { { 1, 2 }, { 3, 4 }, { 5, 6 }, { 7, 8 } };

var span2D = new Span2D<int>(array4);

var row = span2D.GetRowSpan(0);

foreach (var x in row)
{
    Console.Write($"{x} ");
}

Exception: CompilationErrorException

- Field or auto-implemented property cannot be of type 'Span2D<int>' unless it is an instance member of a ref struct.
- Field or auto-implemented property cannot be of type 'Span<int>' unless it is an instance member of a ref struct.
- foreach statement cannot operate on enumerators of type 'Span<int>.Enumerator' in async or iterator methods because 'Span<int>.Enumerator' is a ref struct.

- Field or auto-implemented property cannot be of type 'Span2D<int>' unless it is an instance member of a ref struct.
- Field or auto-implemented property cannot be of type 'Span<int>' unless it is an instance member of a ref struct.
- foreach statement cannot operate on enumerators of type 'Span<int>.Enumerator' in async or iterator methods because 'Span<int>.Enumerator' is a ref struct.

Compile: 1456.056ms | Execution: 0.000ms | React with ❌ to remove this embed.

Henkypenky•2y ago

well it doesn't work here

MODiX•2y ago

Henkypenky#4865

REPL Result: Success

#nuget CommunityToolkit.HighPerformance

F();

void F()
{
    int[,] array4 = { { 1, 2 }, { 3, 4 }, { 5, 6 }, { 7, 8 } };
    var s = new S();
    s.span2D = new Span2D<int>(array4);
    s.row = s.span2D.GetRowSpan(0);

    foreach (var x in s.row)
    {
        Console.Write($"{x} ");
    }
}

ref struct S
{
    public Span2D<int> span2D;
    public Span<int> row;

}

#nuget CommunityToolkit.HighPerformance

F();

void F()
{
    int[,] array4 = { { 1, 2 }, { 3, 4 }, { 5, 6 }, { 7, 8 } };
    var s = new S();
    s.span2D = new Span2D<int>(array4);
    s.row = s.span2D.GetRowSpan(0);

    foreach (var x in s.row)
    {
        Console.Write($"{x} ");
    }
}

ref struct S
{
    public Span2D<int> span2D;
    public Span<int> row;

}

Console Output

1 2

1 2

Compile: 1298.440ms | Execution: 80.430ms | React with ❌ to remove this embed.

Accord•2y ago

Was this issue resolved? If so, run /close - otherwise I will mark this as stale and this post will be archived until there is new activity.

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❔ How to get to one of the arrays in a multidimensional array?