Array.GetLowerBound(Int32) Metoda

Definicja

Pobiera indeks pierwszego elementu określonego wymiaru w tablicy.Gets the index of the first element of the specified dimension in the array.

public:
 int GetLowerBound(int dimension);
public int GetLowerBound (int dimension);
member this.GetLowerBound : int -> int
Public Function GetLowerBound (dimension As Integer) As Integer

Parametry

dimension
Int32

Wymiar liczony od zera tablicy, której indeks początkowy musi zostać określony.A zero-based dimension of the array whose starting index needs to be determined.

Zwraca

Indeks pierwszego elementu określonego wymiaru w tablicy.The index of the first element of the specified dimension in the array.

Wyjątki

dimension jest mniejsza od zera.dimension is less than zero.

—lub—-or- dimension jest równa lub większa niż Rank.dimension is equal to or greater than Rank.

Przykłady

W poniższym przykładzie użyto metod GetLowerBound i GetUpperBound, aby wyświetlić granice tablicy jednowymiarowej i dwuwymiarowej oraz wyświetlić wartości ich elementów tablicy.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 namespace System;

void main()  
{
   // Create a one-dimensional integer array.
   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.
   array<int, 2>^ 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 < rank; 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
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($"Elements from index {lower} to {upper}:");
      // Iterate the array.
      for (int ctr = lower; ctr <= upper; ctr++)
        Console.Write($"{(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($"Number of dimensions: {rank}");      
      for (int ctr = 0; ctr < rank; ctr++)
        Console.WriteLine($"   Dimension {ctr}: " + 
                          $"from {integers2d.GetLowerBound(ctr)} to {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($"      {'\u007b'}{outer}, {inner}{'\u007d'} = " +
                             $"{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
Public Module Example    
    Public Sub Main()
        ' Create a one-dimensional integer array.
        Dim integers() As Integer = { 2, 4, 6, 8, 10, 12, 14, 16, 18, 20 }
        ' Get the upper and lower bound of the array.
        Dim upper As Integer = integers.GetUpperBound(0)
        Dim lower As Integer = integers.GetLowerBound(0)
        Console.WriteLine($"Elements from index {lower} to {upper}:")
        ' Iterate the array.
        For ctr As Integer = lower To upper
           Console.Write("{0}{1}{2}", If(ctr = lower, "   ", ""), 
                                     integers(ctr), 
                                     If(ctr < upper, ", ", vbCrLf))
        Next
        Console.WriteLine()
        
        ' Create a two-dimensional integer array.
        Dim integers2d(,) As Integer = {{2, 4}, {3, 9}, {4, 16}, {5, 25}, 
                                       {6, 36}, {7, 49}, {8, 64}, {9, 81} } 
        ' Get the number of dimensions.                               
        Dim rank As Integer = integers2d.Rank  
        Console.WriteLine($"Number of dimensions: {rank}")      
        For ctr As Integer = 0 To rank - 1
           Console.WriteLine($"   Dimension {ctr}: " +
                             $"from {integers2d.GetLowerBound(ctr)} to {integers2d.GetUpperBound(ctr)}")
        Next
        ' Iterate the 2-dimensional array and display its values.
        Console.WriteLine("   Values of array elements:")
        For outer = integers2d.GetLowerBound(0) To integers2d.GetUpperBound(0)
           For inner = integers2d.GetLowerBound(1) To integers2d.GetUpperBound(1)
              Console.WriteLine($"      {ChrW(&h07b)}{outer}, {inner}{ChrW(&h007d)} = " +
                                $"{integers2d.GetValue(outer, inner)}")
           Next
        Next
    End Sub
End Module
' 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

Uwagi

GetLowerBound(0) zwraca początkowy indeks pierwszego wymiaru tablicy, a GetLowerBound(Rank - 1) zwraca początkowy indeks ostatniego wymiaru tablicy.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.

Metoda GetLowerBound zawsze zwraca wartość wskazującą indeks dolnej granicy tablicy, nawet jeśli tablica jest pusta.The GetLowerBound method always returns a value that indicates the index of the lower bound of the array, even if the array is empty.

Należy zauważyć, że chociaż większość tablic w .NET Framework jest opartych na zero (to oznacza, że metoda GetLowerBound zwraca zero dla każdego wymiaru tablicy), .NET Framework obsługuje tablice, które nie są oparte na zero.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. Takie tablice można utworzyć za pomocą metody CreateInstance(Type, Int32[], Int32[]) i mogą być zwracane z kodu niezarządzanego.Such arrays can be created with the CreateInstance(Type, Int32[], Int32[]) method, and can also be returned from unmanaged code.

Ta metoda jest operacją O(1).This method is an O(1) operation.

Dotyczy

Zobacz też