Cómo: Buscar cadenas mediante los métodos String (Guía de programación de C#)
El tipo string, que es un alias de la clase System.String, proporciona varios métodos útiles para buscar el contenido de una cadena.
Ejemplo
El ejemplo siguiente utiliza los métodos IndexOf, LastIndexOf, StartsWith y EndsWith para buscar las cadenas.
class StringSearch
{
static void Main()
{
string str = "Extension methods have all the capabilities of regular static methods.";
// Write the string and include the quotation marks.
System.Console.WriteLine("\"{0}\"", str);
// Simple comparisons are always case sensitive!
bool test1 = str.StartsWith("extension");
System.Console.WriteLine("Starts with \"extension\"? {0}", test1);
// For user input and strings that will be displayed to the end user,
// use the StringComparison parameter on methods that have it to specify how to match strings.
bool test2 = str.StartsWith("extension", System.StringComparison.CurrentCultureIgnoreCase);
System.Console.WriteLine("Starts with \"extension\"? {0} (ignoring case)", test2);
bool test3 = str.EndsWith(".", System.StringComparison.CurrentCultureIgnoreCase);
System.Console.WriteLine("Ends with '.'? {0}", test3);
// This search returns the substring between two strings, so
// the first index is moved to the character just after the first string.
int first = str.IndexOf("methods") + "methods".Length;
int last = str.LastIndexOf("methods");
string str2 = str.Substring(first, last - first);
System.Console.WriteLine("Substring between \"methods\" and \"methods\": '{0}'", str2);
// Keep the console window open in debug mode
System.Console.WriteLine("Press any key to exit.");
System.Console.ReadKey();
}
}
/*
Output:
"Extension methods have all the capabilities of regular static methods."
Starts with "extension"? False
Starts with "extension"? True (ignoring case)
Ends with '.'? True
Substring between "methods" and "methods": ' have all the capabilities of regular static '
Press any key to exit.
*/
Vea también
Tareas
Cómo: Buscar cadenas mediante expresiones regulares (Guía de programación de C#)