string replace in c#

Question

Hi I have a long string (reading of a html) and I want it to search for string <a href="http://web/sub/index.aspx?articleid=9999">
where 9999 can be any number which can be also 5 digits also eg 1234 or 12345 and I want it to string replace to be <a href="9999.html"

How can I do this?
thanks

Answer 1

Hi

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApp
{
  class Program
  {
    static void Main(string[] args)
    {
      string mycompany = "IBM";
      Console.WriteLine(mycompany);
      Console.WriteLine(mycompany.Replace(mycompany, "Microsoft"));
      Console.ReadKey();
    }
  }
}

Best Regards.
--please don't forget to Accept as answer if the reply is helpful--

Answer 2

See if this will work for you.

using System;  
using System.Collections.Generic;  
using System.Linq;  
using System.Text.RegularExpressions;  
using System.Web;  
  
namespace ConsoleApp1  
{  
    class Program  
    {  
        static void Main(string[] args)  
        {  
            var htmlCode = "<a href=\"http://web/sub/index.aspx?articleid=9999\">";  
  
            DumpHRefs(htmlCode);  
            Console.ReadLine();  
        }  
        static void DumpHRefs(string inputString)  
        {  
            var HRefPattern = @"href\s*=\s*(?:[""'](?<1>[^""']*)[""']|(?<1>\S+))";  
  
            try  
            {  
                var match = Regex.Match(inputString, HRefPattern,   
                    RegexOptions.IgnoreCase |   
                    RegexOptions.Compiled,   
                    TimeSpan.FromSeconds(1));  
  
                while (match.Success)  
                {  
                    Console.WriteLine($"Found href " + match.Groups[1]);  
                    var myUri = new Uri(match.Groups[1].Value);  
                    var articleIdValue = HttpUtility.ParseQueryString(myUri.Query).Get("articleid");  
                      
                    if (!string.IsNullOrWhiteSpace(articleIdValue))  
                    {  
                        Console.WriteLine($"\t{articleIdValue}");  
                    }  
                      
                    match = match.NextMatch();  
                }  
            }  
            catch (RegexMatchTimeoutException)  
            {  
                Console.WriteLine("The matching operation timed out.");  
            }  
        }  
    }  
}  

Edit

Yes, note the 9999 was never searched for in the code but instead the parameters. So the parameter value returned can be concatenated e.g.

using System;  
using System.Collections.Generic;  
using System.Linq;  
using System.Text.RegularExpressions;  
using System.Web;  
  
namespace ConsoleApp1  
{  
    class Program  
    {  
        static void Main(string[] args)  
        {  
  
            var list = new List<string>  
            {  
                "<a href=\"http://web/sub/index.aspx?articleid=9999\">",   
                "<a href=\"http://web/sub/index.aspx?articleid=1\">",   
                "<a href=\"http://web/sub/index.aspx?articleid=123\">"  
            };  
  
            foreach (var item in list)  
            {  
                var results = DumpHRefs(item);  
                Console.WriteLine(item);  
                if (results.Count == 1)  
                {  
                    Console.WriteLine($"\t{results.FirstOrDefault()}");  
                }  
  
            }  
  
  
            Console.ReadLine();  
        }  
        static List<string> DumpHRefs(string inputString)  
        {  
            var resultList = new List<string>();  
              
            var HRefPattern = @"href\s*=\s*(?:[""'](?<1>[^""']*)[""']|(?<1>\S+))";  
  
            try  
            {  
                var match = Regex.Match(inputString, HRefPattern,   
                    RegexOptions.IgnoreCase |   
                    RegexOptions.Compiled,   
                    TimeSpan.FromSeconds(1));  
  
                while (match.Success)  
                {  
  
                    var myUri = new Uri(match.Groups[1].Value);  
                    var articleIdValue = HttpUtility.ParseQueryString(myUri.Query).Get("articleid");  
                      
                    if (!string.IsNullOrWhiteSpace(articleIdValue))  
                    {  
                        resultList.Add($"{articleIdValue}.html");  
                    }  
                      
                    match = match.NextMatch();  
                }  
            }  
            catch (RegexMatchTimeoutException)  
            {  
                Console.WriteLine("The matching operation timed out.");  
            }  
  
            return resultList;  
        }  
    }  
}  

Answer 3

Hi nellie-2760
I suggest you use regular expressions to match urls in the string.
Here is my test code example you can refer to.

static void Main(string[] args)  
{  
    string longS = @"<object>  
                        <node>  
                            <a href='http://web/sub/index.aspx?articleid=9999'>  
                            <a href='http://web/sub/index.aspx?articleid=12345'>  
                        </node>  
                        </object>";  
    string regexString = @"(https?|ftp|file)://[-A-Za-z0-9+&@#/%?=~_|!:,.;]+[-A-Za-z0-9+&@#/%=~_|]";  
    string replacement = Regex.Replace(longS, regexString, "9999.html");  
    Console.WriteLine(replacement);  
    Console.ReadKey();  
}  

The result:

Best Regards,
Daniel Zhang

---

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