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Get the length of a slice from a multi-dimensional array
If I have a one-dimensional array, I can get the length of it quite easily:
var x = moves.Length().
However, if the array is multi-dimensional, .Length() returns the total number of elements. If moves is defined as int[4,2], the moves.Length() returns 8.
Is there a way that I can specify either the X or Y and get the number of elements for that slice?
2 answers
I think what you are looking for is Array.GetLength which:
gets a 32-bit integer that represents the number of elements in the specified dimension of the Array.
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You can use Array.GetUpperBound method
Gets the index of the last element of the specified dimension in the array.
and Array.GetLowerBound one accordingly.
var arr = new int[,]{
{ 1, 2 },
{ 23, 42 }
};
for (int i = arr.GetLowerBound(0); i <= arr.GetUpperBound(0); i++)
{
for (int j = arr.GetLowerBound(0); j <= arr.GetUpperBound(1); j++)
{
Console.Write($"{arr[i, j],3} ");
}
Console.WriteLine();
}
The key difference between this method and Array.GetLength one is that GetUpperBound can be used in case when bounds of an array are arbitrary:
var arrWithNonStandardBounds =
Array.CreateInstance(
typeof(ValueTuple<int, int>),
new[] { 2, 2, },
new int[] { -1, -1 }
);
var n = arrWithNonStandardBounds.GetUpperBound(0);
var m = arrWithNonStandardBounds.GetUpperBound(1);
for (int i = arrWithNonStandardBounds.GetLowerBound(0); i <= n; i++)
{
for (int j = arrWithNonStandardBounds.GetLowerBound(1); j <= m; j++)
{
arrWithNonStandardBounds.SetValue((i, j), i, j);
Console.Write($"{arrWithNonStandardBounds.GetValue(i, j),5} ");
}
Console.WriteLine();
}
It's a rare case especially lately though.
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