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Array.GetLowerBound Method

Gets the index of the first element of the specified dimension in the array.

Namespace:  System
Assembly:  mscorlib (in mscorlib.dll)

public int GetLowerBound(
	int dimension
)

Parameters

dimension
Type: System.Int32

A zero-based dimension of the array whose starting index needs to be determined.

Return Value

Type: System.Int32
The index of the first element of the specified dimension in the array.

ExceptionCondition
IndexOutOfRangeException

dimension is less than zero.

-or-

dimension is equal to or greater than Rank.

GetLowerBound(0) returns the starting index of the first dimension of the array, and GetLowerBound(Rank - 1) returns the starting index of the last dimension of the array.

The GetLowerBound method always returns a value that indicates the index of the lower bound of the array, even if the array is empty.

Note that, although most arrays in the .NET Framework are zero-based (that is, the GetLowerBound method returns zero for each dimension of an array), the .NET Framework does support arrays that are not zero-based. Such arrays can be created with the CreateInstance(Type, Int32[], Int32[]) method, and can also be returned from unmanaged code.

This method is an O(1) operation.

The following example uses the GetLowerBound and GetUpperBound methods to display the bounds of a one-dimensional and two-dimensional array and to display the values of their array elements.

using System;

public class Example
{
   public static void Main()  
   {
      // Create a one-dimensional integer array. 
      int[] integers = { 2, 4, 6, 8, 10, 12, 14, 16, 18, 20 };
      // Get the upper and lower bound of the array. 
      int upper = integers.GetUpperBound(0);
      int lower = integers.GetLowerBound(0);
      Console.WriteLine("Elements from index {0} to {1}:", lower, upper);
      // Iterate the array. 
      for (int ctr = lower; ctr <= upper; ctr++)
        Console.Write("{0}{1}{2}", ctr == lower ? "   " : "", 
                                  integers[ctr], 
                                  ctr < upper ? ", " : Environment.NewLine);

      Console.WriteLine();

      // Create a two-dimensional integer array. 
      int[,] integers2d= { {2, 4}, {3, 9}, {4, 16}, {5, 25}, 
                           {6, 36}, {7, 49}, {8, 64}, {9, 81} }; 
      // Get the number of dimensions.                                
      int rank = integers2d.Rank;  
      Console.WriteLine("Number of dimensions: {0}", rank);      
      for (int ctr = 0; ctr < integers2d.Rank - 1; ctr++)
        Console.WriteLine("   Dimension {0}: from {1} to {2}",
                          ctr, integers2d.GetLowerBound(ctr),
                          integers2d.GetUpperBound(ctr));

      // Iterate the 2-dimensional array and display its values.
      Console.WriteLine("   Values of array elements:");
      for (int outer = integers2d.GetLowerBound(0); outer <= integers2d.GetUpperBound(0);
           outer++)
        for (int inner = integers2d.GetLowerBound(1); inner <= integers2d.GetUpperBound(1);
             inner++)
           Console.WriteLine("      {3}{0}, {1}{4} = {2}", outer, inner,
                             integers2d.GetValue(outer, inner), "{", "}");

   }
}
// The example displays the following output: 
//       Elements from index 0 to 9: 
//          2, 4, 6, 8, 10, 12, 14, 16, 18, 20 
//        
//       Number of dimensions: 2 
//          Dimension 0: from 0 to 7 
//          Dimension 1: from 0 to 1 
//          Values of array elements: 
//             {0, 0} = 2 
//             {0, 1} = 4 
//             {1, 0} = 3 
//             {1, 1} = 9 
//             {2, 0} = 4 
//             {2, 1} = 16 
//             {3, 0} = 5 
//             {3, 1} = 25 
//             {4, 0} = 6 
//             {4, 1} = 36 
//             {5, 0} = 7 
//             {5, 1} = 49 
//             {6, 0} = 8 
//             {6, 1} = 64 
//             {7, 0} = 9 
//             {7, 1} = 81

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

.NET for Windows Store apps

Supported in: Windows 8

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone 8, Silverlight 8.1

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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