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How to: Search Strings Using String Methods (C# Programming Guide)

The string type, which is an alias for the System.String class, provides a number of useful methods for searching the contents of a string.

The following example uses the IndexOf, LastIndexOf, StartsWith, and EndsWith methods to search the strings.


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.     
*/


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