Array.GetLength(Int32) Method

Reference

Definition

Namespace:: System

Assemblies:: mscorlib.dll, System.Runtime.dll

Assemblies:: netstandard.dll, System.Runtime.dll

Assembly:: System.Runtime.dll

Assembly:: mscorlib.dll

Assembly:: netstandard.dll

Source:: Array.CoreCLR.cs

Source:: Array.CoreCLR.cs

Source:: Array.CoreCLR.cs

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

Gets a 32-bit integer that represents the number of elements in the specified dimension of the Array.

public:
 int GetLength(int dimension);

public int GetLength(int dimension);

member this.GetLength : int -> int

Public Function GetLength (dimension As Integer) As Integer

Parameters

dimension: Int32

A zero-based dimension of the Array whose length needs to be determined.

Returns

Int32

A 32-bit integer that represents the number of elements in the specified dimension.

Exceptions

IndexOutOfRangeException

dimension is less than zero.

-or-

dimension is equal to or greater than Rank.

Examples

The following example shows how to use GetLength to display the dimensions of two arrays with different ranks.

using namespace System;

public ref class SamplesArray
{
public:
    static void Main()
    {
        // make a single dimension array
        Array^ MyArray1 = Array::CreateInstance(int::typeid, 5);

        // make a 3 dimensional array
        Array^ MyArray2 = Array::CreateInstance(int::typeid, 5, 3, 2);

        // make an array container
        Array^ BossArray = Array::CreateInstance(Array::typeid, 2);
        BossArray->SetValue(MyArray1, 0);
        BossArray->SetValue(MyArray2, 1);

        int i = 0, j, rank;
        for each (Array^ anArray in BossArray)
        {
            rank = anArray->Rank;
            if (rank > 1)
            {
                Console::WriteLine("Lengths of {0:d} dimension array[{1:d}]", rank, i);
                // show the lengths of each dimension
                for (j = 0; j < rank; j++)
                {
                    Console::WriteLine("    Length of dimension({0:d}) = {1:d}", j, anArray->GetLength(j));
                }
            }
            else
            {
                Console::WriteLine("Lengths of single dimension array[{0:d}]", i);
            }
            // show the total length of the entire array or all dimensions
            Console::WriteLine("    Total length of the array = {0:d}", anArray->Length);
            Console::WriteLine();
            i++;
        }
    }
};

int main()
{
    SamplesArray::Main();
}

/*
This code produces the following output:

Lengths of single dimension array[0]
    Total length of the array = 5

Lengths of 3 dimension array[1]
    Length of dimension(0) = 5
    Length of dimension(1) = 3
    Length of dimension(2) = 2
    Total length of the array = 30
*/

using System;

public class SamplesArray
{
    public static void Main()
    {
        // make a single dimension array
        Array MyArray1 = Array.CreateInstance(typeof(int), 5);

        // make a 3 dimensional array
        Array MyArray2 = Array.CreateInstance(typeof(int), 5, 3, 2);

        // make an array container
        Array BossArray = Array.CreateInstance(typeof(Array), 2);
        BossArray.SetValue(MyArray1, 0);
        BossArray.SetValue(MyArray2, 1);

        int i = 0, j, rank;
        foreach (Array anArray in BossArray)
        {
            rank = anArray.Rank;
            if (rank > 1)
            {
                Console.WriteLine("Lengths of {0:d} dimension array[{1:d}]", rank, i);
                // show the lengths of each dimension
                for (j = 0; j < rank; j++)
                {
                    Console.WriteLine("    Length of dimension({0:d}) = {1:d}", j, anArray.GetLength(j));
                }
            }
            else
            {
                Console.WriteLine("Lengths of single dimension array[{0:d}]", i);
            }
            // show the total length of the entire array or all dimensions
            Console.WriteLine("    Total length of the array = {0:d}", anArray.Length);
            Console.WriteLine();
            i++;
        }
    }
}

/*
This code produces the following output:

Lengths of single dimension array[0]
    Total length of the array = 5

Lengths of 3 dimension array[1]
    Length of dimension(0) = 5
    Length of dimension(1) = 3
    Length of dimension(2) = 2
    Total length of the array = 30
*/

open System

// make a single dimension array
let myArray1 = Array.zeroCreate<int> 5

// make a 3 dimensional array
let myArray2 = Array3D.zeroCreate<int> 5 3 2

// make an array container
let bossArray: Array [] = 
    [|  myArray1
        myArray2 |]

let mutable i = 0
for anArray in bossArray do
    let rank = anArray.Rank;
    if rank > 1 then
        printfn $"Lengths of {rank:d} dimension array[{i:d}]"
        // show the lengths of each dimension
        for j = 0 to rank - 1 do
            printfn $"    Length of dimension({j:d}) = {anArray.GetLength(j):d}"
    else
        printfn $"Lengths of single dimension array[{i:d}]"

    // show the total length of the entire array or all dimensions
    printfn $"    Total length of the array = {anArray.Length:d}\n"
    i <- i + 1


// This code produces the following output:
//     Lengths of single dimension array[0]
//         Total length of the array = 5
//
//     Lengths of 3 dimension array[1]
//         Length of dimension(0) = 5
//         Length of dimension(1) = 3
//         Length of dimension(2) = 2
//     Total length of the array = 30

Public Class SamplesArray
    Public Shared Sub Main()
        ' make a single dimension array
        Dim MyArray1 As Array = Array.CreateInstance(GetType(Integer), 5)

        ' make a 3 dimensional array
        Dim MyArray2 As Array = Array.CreateInstance(GetType(Integer), 5, 3, 2)

        ' make an array container
        Dim BossArray As Array = Array.CreateInstance(GetType(Array), 2)
        BossArray.SetValue(MyArray1, 0)
        BossArray.SetValue(MyArray2, 1)

        Dim i As Integer = 0
        Dim j As Integer
        Dim rank As Integer
        For Each anArray As Array In BossArray
            rank = anArray.Rank
            If rank > 1
                Console.WriteLine("Lengths of {0:d} dimension array[{1:d}]", rank, i)
                ' show the lengths of each dimension
                For j = 0 To rank - 1
                    Console.WriteLine("    Length of dimension({0:d}) = {1:d}", j, anArray.GetLength(j))
                Next j
            Else
                Console.WriteLine("Lengths of single dimension array[{0:d}]", i)
            End If
            ' show the total length of the entire array or all dimensions
            Console.WriteLine("    Total length of the array = {0:d}", anArray.Length)
            Console.WriteLine()
            i = i + 1
        Next anArray
    End Sub
End Class

'This code produces the following output:
'
'Lengths of single dimension array[0]
'    Total length of the array = 5
'
'Lengths of 3 dimension array[1]
'    Length of dimension(0) = 5
'    Length of dimension(1) = 3
'    Length of dimension(2) = 2
'    Total length of the array = 30

Remarks

An example of GetLength is GetLength(0), which returns the number of elements in the first dimension of the Array.

This method is an O(1) operation.

Applies to

Product	Versions
.NET	Core 1.0, Core 1.1, Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9, 10
.NET Framework	1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
.NET Standard	1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 2.0, 2.1
UWP	10.0

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