.Net(C#) 实现replace字符串替换只替换一次的方法

1、使用StringBuilder替换

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Text.RegularExpressions;namespace ConsoleApplication2{    class Program    {        static void Main(string[] args)        {            string str = "hello world! wonhero!!!";            StringBuilder sb = new StringBuilder(str);            str = sb.Replace("!", "b", 0, str.IndexOf("!") + 1).ToString(); ;//指定替换的范围实现替换一次,并且指定范围中要只有一个替换的字符串            Console.WriteLine(str);//输出：hello worldb wonhero!!!            Console.ReadKey();        }    }}

2、使用正则表达式(Regex)替换

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Text.RegularExpressions;namespace ConsoleApplication2{    class Program    {        static void Main(string[] args)        {            string str = "hello world! wonhero!!!";            Regex regex = new Regex("!");//要替换字符串"!"            str = regex.Replace(str, "b", 1);//最后一个参数是替换的次数            Console.WriteLine(str);//输出：hello worldb wonhero!!!            Console.ReadKey();        }    }}

3、使用IndexOf和Substring替换

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Text.RegularExpressions;namespace ConsoleApplication2{    class Program    {        static void Main(string[] args)        {            string str = "hello world! wonhero!!!";            StringBuilder sb = new StringBuilder(str);            int index = str.IndexOf("!");            str = str.Substring(0, index) + "b" + str.Substring(index + 1);//指定替换的范围实现替换一次,并且指定范围中要只有一个替换的字符串            Console.WriteLine(str);//输出：hello worldb wonhero!!!            Console.ReadKey();        }    }}

4、通过扩展方法实现ReplaceOne

扩展方法实现代码：

using System;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;

namespace ConsoleApplication2
{
    public static class StringReplace
    {
    public static string ReplaceOne(this string str, string oldStr, string newStr)
        {
               StringBuilder sb = new StringBuilder(str);
            int index = str.IndexOf(oldStr);
            if (index > -1)
                return str.Substring(0, index) + newStr + str.Substring(index + oldStr.Length);
            return str;
        }
     }
}

调用代码：

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Text.RegularExpressions;namespace ConsoleApplication2{    class Program    {        static void Main(string[] args)        {            string str = "hello world! wonhero!!!";            str = str.ReplaceOne("!","b");//通过扩展方法替换            Console.WriteLine(str);//输出：hello worldb wonhero!!!            Console.ReadKey();        }    }}