Char.GetNumericValue Método

Definição

Converte um caractere Unicode numérico especificado em um número de ponto flutuante de precisão dupla.Converts a specified numeric Unicode character to a double-precision floating-point number.

Sobrecargas

GetNumericValue(String, Int32)

Converte o caractere Unicode numérico na posição especificada contido em uma cadeia de caracteres especificada em um número de ponto flutuante de precisão dupla.Converts the numeric Unicode character at the specified position in a specified string to a double-precision floating point number.

GetNumericValue(Char)

Converte o caractere Unicode numérico especificado em um número de ponto flutuante de precisão dupla.Converts the specified numeric Unicode character to a double-precision floating point number.

GetNumericValue(String, Int32)

Converte o caractere Unicode numérico na posição especificada contido em uma cadeia de caracteres especificada em um número de ponto flutuante de precisão dupla.Converts the numeric Unicode character at the specified position in a specified string to a double-precision floating point number.

public:
 static double GetNumericValue(System::String ^ s, int index);
public static double GetNumericValue (string s, int index);
static member GetNumericValue : string * int -> double
Public Shared Function GetNumericValue (s As String, index As Integer) As Double

Parâmetros

s
String

Um String.A String.

index
Int32

A posição do caractere em s.The character position in s.

Retornos

O valor numérico do caractere na posição index em s se esse caractere representar um número; caso contrário, -1.The numeric value of the character at position index in s if that character represents a number; otherwise, -1.

Exceções

s é null.s is null.

index é menor que zero ou maior que a última posição em s.index is less than zero or greater than the last position in s.

Exemplos

O exemplo de código a seguir demonstra GetNumericValue.The following code example demonstrates GetNumericValue.

using namespace System;
int main()
{
   String^ str =  "input: 1";
   Console::WriteLine( Char::GetNumericValue( '8' ) ); // Output: "8"
   Console::WriteLine( Char::GetNumericValue( str, 7 ) ); // Output: "1"
}

using System;

public class GetNumericValueSample {
    public static void Main() {
        string str = "input: 1";

        Console.WriteLine(Char.GetNumericValue('8'));		// Output: "8"
        Console.WriteLine(Char.GetNumericValue(str, 7));	// Output: "1"
    }
}
Module GetNumericValueSample
    Sub Main()
        Dim str As String
        str = "input: 1"

        Console.WriteLine(Char.GetNumericValue("8"c))       ' Output: "8"
        Console.WriteLine(Char.GetNumericValue(str, 7))     ' Output: "1"
    End Sub
End Module

Comentários

O parâmetro s deve ser a representação de cadeia de caracteres de um valor numérico.The s parameter must be the string representation of a numeric value. Por exemplo, se o caractere na posição index em s for "5", o valor de retorno será 5.For example, if the character at position index in s is "5", the return value is 5. No entanto, se o caractere na posição index em s for "z", o valor de retorno será-1.However, if the character at position index in s is "z", the return value is -1.

As posições de caractere em uma cadeia de caracteres são indexadas a partir de zero.Character positions in a string are indexed starting from zero.

Um caractere tem um valor numérico associado se e somente se for um membro de uma das seguintes UnicodeCategory categorias: DecimalDigitNumber, LetterNumberou OtherNumber.A character has an associated numeric value if and only if it is a member of one of the following UnicodeCategory categories: DecimalDigitNumber, LetterNumber, or OtherNumber.

Se o objeto Char na posição index for o primeiro caractere de um par substituto válido, o método GetNumericValue(String, Int32) determinará se o par substituto forma um dígito numérico.If the Char object at position index is the first character of a valid surrogate pair, the GetNumericValue(String, Int32) method determines whether the surrogate pair forms a numeric digit. Por exemplo, o sistema de numeração Aegean consiste em pontos de código de U+10107 a U+10133.For example, the Aegean numbering system consists of code points U+10107 through U+10133. O exemplo a seguir usa o método ConvertFromUtf32 para criar uma instância de uma cadeia de caracteres que representa cada número de Aegean.The following example uses the ConvertFromUtf32 method to instantiate a string that represents each Aegean number. Como a saída do exemplo mostra, o método GetNumericValue(String, Int32) retorna o valor numérico correto se for passado o substituto alto de um número Aegean.As the output from the example shows, the GetNumericValue(String, Int32) method returns the correct numeric value if it is passed the high surrogate of an Aegean number. No entanto, se for passado o substituto baixo, ele considerará apenas o baixo substituto em isolamento e retornará-1.However, if it is passed the low surrogate, it considers only the low surrogate in isolation and returns -1.

// Define a UTF32 value for each character in the 
// Aegean numbering system.
for (int utf32 = 0x10107; utf32 <= 0x10133; utf32++) {
   string surrogate = Char.ConvertFromUtf32(utf32);
   for (int ctr = 0; ctr < surrogate.Length; ctr++) 
      Console.Write("U+{0:X4} at position {1}: {2}     ", 
                        Convert.ToUInt16(surrogate[ctr]), ctr,  
                        Char.GetNumericValue(surrogate, ctr));

   Console.WriteLine();
}    
// The example displays the following output:
//       U+D800 at position 0: 1     U+DD07 at position 1: -1
//       U+D800 at position 0: 2     U+DD08 at position 1: -1
//       U+D800 at position 0: 3     U+DD09 at position 1: -1
//       U+D800 at position 0: 4     U+DD0A at position 1: -1
//       U+D800 at position 0: 5     U+DD0B at position 1: -1
//       U+D800 at position 0: 6     U+DD0C at position 1: -1
//       U+D800 at position 0: 7     U+DD0D at position 1: -1
//       U+D800 at position 0: 8     U+DD0E at position 1: -1
//       U+D800 at position 0: 9     U+DD0F at position 1: -1
//       U+D800 at position 0: 10     U+DD10 at position 1: -1
//       U+D800 at position 0: 20     U+DD11 at position 1: -1
//       U+D800 at position 0: 30     U+DD12 at position 1: -1
//       U+D800 at position 0: 40     U+DD13 at position 1: -1
//       U+D800 at position 0: 50     U+DD14 at position 1: -1
//       U+D800 at position 0: 60     U+DD15 at position 1: -1
//       U+D800 at position 0: 70     U+DD16 at position 1: -1
//       U+D800 at position 0: 80     U+DD17 at position 1: -1
//       U+D800 at position 0: 90     U+DD18 at position 1: -1
//       U+D800 at position 0: 100     U+DD19 at position 1: -1
//       U+D800 at position 0: 200     U+DD1A at position 1: -1
//       U+D800 at position 0: 300     U+DD1B at position 1: -1
//       U+D800 at position 0: 400     U+DD1C at position 1: -1
//       U+D800 at position 0: 500     U+DD1D at position 1: -1
//       U+D800 at position 0: 600     U+DD1E at position 1: -1
//       U+D800 at position 0: 700     U+DD1F at position 1: -1
//       U+D800 at position 0: 800     U+DD20 at position 1: -1
//       U+D800 at position 0: 900     U+DD21 at position 1: -1
//       U+D800 at position 0: 1000     U+DD22 at position 1: -1
//       U+D800 at position 0: 2000     U+DD23 at position 1: -1
//       U+D800 at position 0: 3000     U+DD24 at position 1: -1
//       U+D800 at position 0: 4000     U+DD25 at position 1: -1
//       U+D800 at position 0: 5000     U+DD26 at position 1: -1
//       U+D800 at position 0: 6000     U+DD27 at position 1: -1
//       U+D800 at position 0: 7000     U+DD28 at position 1: -1
//       U+D800 at position 0: 8000     U+DD29 at position 1: -1
//       U+D800 at position 0: 9000     U+DD2A at position 1: -1
//       U+D800 at position 0: 10000     U+DD2B at position 1: -1
//       U+D800 at position 0: 20000     U+DD2C at position 1: -1
//       U+D800 at position 0: 30000     U+DD2D at position 1: -1
//       U+D800 at position 0: 40000     U+DD2E at position 1: -1
//       U+D800 at position 0: 50000     U+DD2F at position 1: -1
//       U+D800 at position 0: 60000     U+DD30 at position 1: -1
//       U+D800 at position 0: 70000     U+DD31 at position 1: -1
//       U+D800 at position 0: 80000     U+DD32 at position 1: -1
//       U+D800 at position 0: 90000     U+DD33 at position 1: -1
' Define a UTF32 value for each character in the 
' Aegean numbering system.
For utf32 As Integer = &h10107 To &h10133
   Dim surrogate As String = Char.ConvertFromUtf32(utf32)
   For ctr As Integer = 0 To surrogate.Length - 1
      Console.Write("U+{0:X4} at position {1}: {2}     ", 
                        Convert.ToUInt16(surrogate(ctr)), ctr,  
                        Char.GetNumericValue(surrogate, ctr))
   Next
   Console.WriteLine()
Next    
' The example displays the following output:
'       U+D800 at position 0: 1     U+DD07 at position 1: -1
'       U+D800 at position 0: 2     U+DD08 at position 1: -1
'       U+D800 at position 0: 3     U+DD09 at position 1: -1
'       U+D800 at position 0: 4     U+DD0A at position 1: -1
'       U+D800 at position 0: 5     U+DD0B at position 1: -1
'       U+D800 at position 0: 6     U+DD0C at position 1: -1
'       U+D800 at position 0: 7     U+DD0D at position 1: -1
'       U+D800 at position 0: 8     U+DD0E at position 1: -1
'       U+D800 at position 0: 9     U+DD0F at position 1: -1
'       U+D800 at position 0: 10     U+DD10 at position 1: -1
'       U+D800 at position 0: 20     U+DD11 at position 1: -1
'       U+D800 at position 0: 30     U+DD12 at position 1: -1
'       U+D800 at position 0: 40     U+DD13 at position 1: -1
'       U+D800 at position 0: 50     U+DD14 at position 1: -1
'       U+D800 at position 0: 60     U+DD15 at position 1: -1
'       U+D800 at position 0: 70     U+DD16 at position 1: -1
'       U+D800 at position 0: 80     U+DD17 at position 1: -1
'       U+D800 at position 0: 90     U+DD18 at position 1: -1
'       U+D800 at position 0: 100     U+DD19 at position 1: -1
'       U+D800 at position 0: 200     U+DD1A at position 1: -1
'       U+D800 at position 0: 300     U+DD1B at position 1: -1
'       U+D800 at position 0: 400     U+DD1C at position 1: -1
'       U+D800 at position 0: 500     U+DD1D at position 1: -1
'       U+D800 at position 0: 600     U+DD1E at position 1: -1
'       U+D800 at position 0: 700     U+DD1F at position 1: -1
'       U+D800 at position 0: 800     U+DD20 at position 1: -1
'       U+D800 at position 0: 900     U+DD21 at position 1: -1
'       U+D800 at position 0: 1000     U+DD22 at position 1: -1
'       U+D800 at position 0: 2000     U+DD23 at position 1: -1
'       U+D800 at position 0: 3000     U+DD24 at position 1: -1
'       U+D800 at position 0: 4000     U+DD25 at position 1: -1
'       U+D800 at position 0: 5000     U+DD26 at position 1: -1
'       U+D800 at position 0: 6000     U+DD27 at position 1: -1
'       U+D800 at position 0: 7000     U+DD28 at position 1: -1
'       U+D800 at position 0: 8000     U+DD29 at position 1: -1
'       U+D800 at position 0: 9000     U+DD2A at position 1: -1
'       U+D800 at position 0: 10000     U+DD2B at position 1: -1
'       U+D800 at position 0: 20000     U+DD2C at position 1: -1
'       U+D800 at position 0: 30000     U+DD2D at position 1: -1
'       U+D800 at position 0: 40000     U+DD2E at position 1: -1
'       U+D800 at position 0: 50000     U+DD2F at position 1: -1
'       U+D800 at position 0: 60000     U+DD30 at position 1: -1
'       U+D800 at position 0: 70000     U+DD31 at position 1: -1
'       U+D800 at position 0: 80000     U+DD32 at position 1: -1
'       U+D800 at position 0: 90000     U+DD33 at position 1: -1

GetNumericValue(Char)

Converte o caractere Unicode numérico especificado em um número de ponto flutuante de precisão dupla.Converts the specified numeric Unicode character to a double-precision floating point number.

public:
 static double GetNumericValue(char c);
public static double GetNumericValue (char c);
static member GetNumericValue : char -> double
Public Shared Function GetNumericValue (c As Char) As Double

Parâmetros

c
Char

O caractere Unicode a ser convertido.The Unicode character to convert.

Retornos

O valor numérico de c se esse caractere representar um número; caso contrário, -1.0.The numeric value of c if that character represents a number; otherwise, -1.0.

Exemplos

O exemplo a seguir demonstra GetNumericValue.The following example demonstrates GetNumericValue.

using namespace System;
int main()
{
   String^ str =  "input: 1";
   Console::WriteLine( Char::GetNumericValue( '8' ) ); // Output: "8"
   Console::WriteLine( Char::GetNumericValue( str, 7 ) ); // Output: "1"
}

using System;

public class GetNumericValueSample {
    public static void Main() {
        string str = "input: 1";

        Console.WriteLine(Char.GetNumericValue('8'));		// Output: "8"
        Console.WriteLine(Char.GetNumericValue(str, 7));	// Output: "1"
    }
}
Module GetNumericValueSample
    Sub Main()
        Dim str As String
        str = "input: 1"

        Console.WriteLine(Char.GetNumericValue("8"c))       ' Output: "8"
        Console.WriteLine(Char.GetNumericValue(str, 7))     ' Output: "1"
    End Sub
End Module

Comentários

O parâmetro c deve ser a representação Char de um valor numérico.The c parameter must be the Char representation of a numeric value. Por exemplo, se c for "5", o valor de retorno será 5.For example, if c is "5", the return value is 5. No entanto, se c for "z", o valor de retorno será-1,0.However, if c is "z", the return value is -1.0.

Um caractere tem um valor numérico associado se e somente se for um membro de uma das seguintes UnicodeCategory categorias: DecimalDigitNumber, LetterNumberou OtherNumber.A character has an associated numeric value if and only if it is a member of one of the following UnicodeCategory categories: DecimalDigitNumber, LetterNumber, or OtherNumber.

O método GetNumericValue pressupõe que c corresponde a um único caractere linguístico e verifica se esse caractere pode ser convertido em um dígito decimal.The GetNumericValue method assumes that c corresponds to a single linguistic character and checks whether that character can be converted to a decimal digit. No entanto, alguns números no padrão Unicode são representados por dois objetos Char que formam um par alternativo.However, some numbers in the Unicode standard are represented by two Char objects that form a surrogate pair. Por exemplo, o sistema de numeração Aegean consiste em pontos de código de U+10107 a U+10133.For example, the Aegean numbering system consists of code points U+10107 through U+10133. O exemplo a seguir usa o método ConvertFromUtf32 para instanciar uma cadeia de caracteres que representa AEGEAN NUMBER ONE.The following example uses the ConvertFromUtf32 method to instantiate a string that represents AEGEAN NUMBER ONE. Como a saída do exemplo mostra, o método GetNumericValue(Char) retornará-1 se for passado como um substituto alto ou um substituto baixo desse caractere.As the output from the example shows, the GetNumericValue(Char) method returns -1 if it is passed either a high surrogate or a low surrogate of this character.

int utf32 = 0x10107;       // AEGEAN NUMBER ONE
string surrogate = Char.ConvertFromUtf32(utf32);
foreach (var ch in surrogate)
   Console.WriteLine("U+{0:X4}: {1}    ", Convert.ToUInt16(ch), 
                                          Char.GetNumericValue(ch));

// The example displays the following output:
//       U+D800: -1
//       U+DD07: -1
Dim utf32 As Integer = &h10107       ' AEGEAN NUMBER ONE
Dim surrogate As String = Char.ConvertFromUtf32(utf32)
For Each ch In surrogate
   Console.WriteLine("U+{0:X4}: {1}    ", Convert.ToUInt16(ch), 
                                          Char.GetNumericValue(ch))
Next
' The example displays the following output:
'       U+D800: -1
'       U+DD07: -1

Aplica-se a