String.Contains Método

Source:

String.Searching.cs

Source:

String.Searching.cs

Source:

String.Searching.cs

public:
 bool Contains(System::String ^ value, StringComparison comparisonType);

public bool Contains (string value, StringComparison comparisonType);

member this.Contains : string * StringComparison -> bool

Public Function Contains (value As String, comparisonType As StringComparison) As Boolean

Parámetros

Devoluciones

Es true si el parámetro value aparece en esta cadena o si value es la cadena vacía (""); en caso contrario, es false.

Source:

String.Searching.cs

Source:

String.Searching.cs

Source:

String.Searching.cs

public:
 bool Contains(char value, StringComparison comparisonType);

public bool Contains (char value, StringComparison comparisonType);

member this.Contains : char * StringComparison -> bool

Public Function Contains (value As Char, comparisonType As StringComparison) As Boolean

Parámetros

Devoluciones

true si el parámetro de value aparece dentro de esta cadena; en caso contrario, false.

Source:

String.Searching.cs

Source:

String.Searching.cs

Source:

String.Searching.cs

public:
 bool Contains(System::String ^ value);

public bool Contains (string value);

member this.Contains : string -> bool

Public Function Contains (value As String) As Boolean

Parámetros

Devoluciones

Es true si el parámetro value aparece en esta cadena o si value es la cadena vacía (""); en caso contrario, es false.

Excepciones

Ejemplos

En el ejemplo siguiente se determina si la cadena "fox" es una subcadena de una cita conocida. Si se encuentra "fox" en la cadena, también muestra su posición inicial.

using namespace System;

int main()
{
   String^ s1 = "The quick brown fox jumps over the lazy dog";
   String^ s2 = "fox";
   bool b = s1->Contains( s2 );
   Console::WriteLine( "Is the string, s2, in the string, s1?: {0}", b );
   if (b) {
      int index = s1->IndexOf(s2);
      if (index >= 0)
         Console::WriteLine("'{0} begins at character position {1}",
                            s2, index + 1);
   }
}
// This example displays the following output:
//    'fox' is in the string 'The quick brown fox jumps over the lazy dog': True
//    'fox begins at character position 17

string s1 = "The quick brown fox jumps over the lazy dog";
string s2 = "fox";
bool b = s1.Contains(s2);
Console.WriteLine("'{0}' is in the string '{1}': {2}",
                s2, s1, b);
if (b) {
    int index = s1.IndexOf(s2);
    if (index >= 0)
        Console.WriteLine("'{0} begins at character position {1}",
                      s2, index + 1);
}
// This example displays the following output:
//    'fox' is in the string 'The quick brown fox jumps over the lazy dog': True
//    'fox begins at character position 17

let s1 = "The quick brown fox jumps over the lazy dog"
let s2 = "fox"
let b = s1.Contains s2
printfn $"'{s2}' is in the string '{s1}': {b}"
if b then
    let index = s1.IndexOf s2
    if index >= 0 then
        printfn $"'{s2} begins at character position {index + 1}"
// This example displays the following output:
//    'fox' is in the string 'The quick brown fox jumps over the lazy dog': True
//    'fox begins at character position 17

Class Example
   Public Shared Sub Main()
      Dim s1 As String = "The quick brown fox jumps over the lazy dog"
      Dim s2 As String = "fox"
      Dim b As Boolean = s1.Contains(s2)
      Console.WriteLine("'{0}' is in the string '{1}': {2}",
                        s2, s1, b)
      If b Then
          Dim index As Integer = s1.IndexOf(s2)
          If index >= 0 Then
             Console.WriteLine("'{0} begins at character position {1}",
                               s2, index + 1)
          End If
       End If
   End Sub
End Class
'
' This example displays the following output:
'    'fox' is in the string 'The quick brown fox jumps over the lazy dog': True
'    'fox begins at character position 17

Comentarios

Este método realiza una comparación ordinal (sin distinción entre mayúsculas y minúsculas y sin distinción entre referencias culturales). La búsqueda comienza en la primera posición de carácter de esta cadena y continúa hasta la última posición de carácter.

Para realizar una comparación que distingue entre mayúsculas y minúsculas o ordinales:

• En .NET Core 2.1 y versiones posteriores: llame a la Contains(String, StringComparison) sobrecarga en su lugar.

• En .NET Framework: Create un método personalizado. En el ejemplo siguiente se muestra un enfoque de este tipo. Define un String método de extensión que incluye un StringComparison parámetro e indica si una cadena contiene una subcadena cuando se usa la forma especificada de comparación de cadenas.

using System;

public static class StringExtensions
{
   public static bool Contains(this String str, String substring, 
                               StringComparison comp)
   {                            
        if (substring == null)
            throw new ArgumentNullException("substring", 
                                         "substring cannot be null.");
        else if (! Enum.IsDefined(typeof(StringComparison), comp))
            throw new ArgumentException("comp is not a member of StringComparison",
                                     "comp");

        return str.IndexOf(substring, comp) >= 0;                      
   }
}

open System
open System.Runtime.CompilerServices

[<Extension>]
type StringExtensions =
    [<Extension>]
    static member Contains(str: string, substring, comp: StringComparison) =
        if substring = null then
            invalidArg "substring" "substring cannot be null"
        if Enum.IsDefined(typeof<StringComparison>, comp) |> not then
            invalidArg "comp" "comp is not a member of StringComparison"
        str.IndexOf(substring, comp) >= 0

String s = "This is a string.";
String sub1 = "this";
Console.WriteLine("Does '{0}' contain '{1}'?", s, sub1);
StringComparison comp = StringComparison.Ordinal;
Console.WriteLine("   {0:G}: {1}", comp, s.Contains(sub1, comp));

comp = StringComparison.OrdinalIgnoreCase;
Console.WriteLine("   {0:G}: {1}", comp, s.Contains(sub1, comp));

// The example displays the following output:
//       Does 'This is a string.' contain 'this'?
//          Ordinal: False
//          OrdinalIgnoreCase: True

let s = "This is a string."
let sub1 = "this"
printfn $"Does '{s}' contain '{sub1}'?"
let comp = StringComparison.Ordinal
printfn $"   {comp:G}: {s.Contains(sub1, comp)}"

let comp2 = StringComparison.OrdinalIgnoreCase
printfn $"   {comp2:G}: {s.Contains(sub1, comp2)}"

// The example displays the following output:
//       Does 'This is a string.' contain 'this'?
//          Ordinal: False
//          OrdinalIgnoreCase: True

Imports System.Runtime.CompilerServices

Module StringExtensions
   <Extension()>
   Public Function Contains(str As String, substring As String, 
                            comp As StringComparison) As Boolean
      If substring Is Nothing Then
         Throw New ArgumentNullException("substring", 
                                         "substring cannot be null.")
      Else If Not [Enum].IsDefined(GetType(StringComparison), comp)
         Throw New ArgumentException("comp is not a member of StringComparison",
                                     "comp")
      End If                               
      Return str.IndexOf(substring, comp) >= 0                      
   End Function
End Module

Public Module Example
   Public Sub Main
      Dim s As String = "This is a string."
      Dim sub1 As String = "this"
      Console.WriteLine("Does '{0}' contain '{1}'?", s, sub1)
      Dim comp As StringComparison = StringComparison.Ordinal
      Console.WriteLine("   {0:G}: {1}", comp, s.Contains(sub1, comp))
      
      comp = StringComparison.OrdinalIgnoreCase
      Console.WriteLine("   {0:G}: {1}", comp, s.Contains(sub1, comp))
   End Sub
End Module
' The example displays the following output:
'       Does 'This is a string.' contain 'this'?
'          Ordinal: False
'          OrdinalIgnoreCase: True

Si está interesado en la posición de la subcadena value en la instancia actual, puede llamar al IndexOf método para obtener la posición inicial de su primera aparición, o bien puede llamar al LastIndexOf método para obtener la posición inicial de su última aparición. En el ejemplo se incluye una llamada al IndexOf(String) método si se encuentra una subcadena en una instancia de cadena.

Consulte también

• IndexOf(Char)
• LastIndexOf(String)

Source:

String.Searching.cs

Source:

String.Searching.cs

Source:

String.Searching.cs

public:
 bool Contains(char value);

public bool Contains (char value);

member this.Contains : char -> bool

Public Function Contains (value As Char) As Boolean

Parámetros

Devoluciones

true si el parámetro de value aparece dentro de esta cadena; en caso contrario, false.

Comentarios

Este método realiza una comparación ordinal (sin distinción entre mayúsculas y minúsculas y sin distinción entre referencias culturales).