如何:使用字符串方法搜索字符串(C# 编程指南) - C# 编程指南

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如何:使用字符串方法搜索字符串(C# 编程指南)

发布于 2019-11-12 字数2273 浏览 781 评论 0

string 类型(它是 System..::.String 类的别名)为搜索字符串的内容提供了许多有用的方法。

示例

下面的示例使用 IndexOf、LastIndexOf、StartsWith 和 EndsWith 方法搜素字符串。

C#  复制代码
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.     
*/

请参见

任务

如何:使用正则表达式搜索字符串(C# 编程指南)

概念

C# 编程指南LINQ 和字符串

参考

字符串(C# 编程指南)

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