Array.GetLength(Int32) Method

Reference

Definition

Namespace:: System

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

Jaa