CODEWITHSUNDEEP
c#arrays
Hal Heinrich
Hal Heinrich

Reputation: 642

How do I initialize a two-dimensional array using Array.Empty()?

Here's the code:

int[,] Arr;
Arr = Array.Empty();

And here's the compile error for the second line:

Error CS0411 The type arguments for method 'Array.Empty()' cannot be inferred from the usage. Try specifying the type arguments explicitly.

This should be a simple syntax fix, but I haven't been able to get it.

Upvotes: 2

Views: 5341

Answers (1)

41686d6564
41686d6564

Reputation: 19641

You may use:

int[,] Arr = new int[0, 0];

Or if you'd like to replicate the Empty() method for multidimensional arrays, you could write a helper class for that:

static class MultiDimArray
{
    public static T[,] Empty2D<T>() => new T[0, 0];

    public static T[,,] Empty3D<T>() => new T[0, 0, 0];

    // Etc.
}

Usage:

int[,] Arr = MultiDimArray.Empty2D<int>();

To take this a step further (and actually make it useful), we can make this work exactly like Array.Empty(), and thus avoid unnecessary memory allocation by using static readonly fields so that they're only initialized once:

static class MultiDimArray
{
    public static T[,] Empty2D<T>() => Empty2DArray<T>.Value;
    public static T[,,] Empty3D<T>() => Empty3DArray<T>.Value;
    // Etc.

    private class Empty2DArray<T> { public static readonly T[,] Value = new T[0, 0]; }
    private class Empty3DArray<T> { public static readonly T[,,] Value = new T[0, 0, 0]; }
    // Etc.
}

Upvotes: 6

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