How to test if an object is an array of arrays/jagged array

Question

I'm trying to test what kind of array an object is: 1D, 2D, or an array of arrays/jagged array.

Here's what I tried:

    if (o is Array && ((Array)o).Rank == 2) {
        Console.Write ("2D-Array:  ");
    } 
    /* else if (o[0] is Array) {
        Console.WriteLine ("Jagged Array:  ");
    } */
    else if (o is Array) {
        Console.Write ("1D-Array:  ");
    }

But the middle test doesn't work because Cannot apply indexing with [] to an expression of type 'object'

How else could you do this? Thanks in advance.

You can use GetValue. But does this new object[]{new object[0],3} a jagged array? — user4003407
– user4003407, Commented Jan 1, 2015 at 8:02

Moti Azu · Accepted Answer · 2015-01-01 10:20:37Z

3

Since o is an object and you did not box it as an array, this code won't compile. Here's an easier way:

var arr = o as Array;
if(arr != null) 
{
    if(arr.Rank == 2) 
    {
        Console.Write ("2D-Array:  ");
    } 
    else if (arr.Length > 0 && arr.GetValue(0) is Array) 
    {
        Console.WriteLine ("Jagged Array:  ");
    } 
    else
    {
        Console.Write ("1D-Array:  ");
    }
}

edited Jan 1, 2015 at 10:20

answered Jan 1, 2015 at 8:18

Moti Azu

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2 Comments

user4003407 Over a year ago

You can not index Array either.

Moti Azu Over a year ago

@PetSerAl Correct, I saw Array implements IList but I didn't make sure the implementation wasn't explicit. Fixed.

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