Regex does not work

Hello Guys,

few days ago a had got a regex formula to get a telephone number from a string it works in uipath but when i used it in a c# code:

string labphone = System.Text.RegularExpressions.Regex.Match(item, @"(?<=l:|l :).[0-9\s0-9\W]").Value;
it did not work, also when testing the regex alone:

can you provide the sample and string ?

tél : 01 88 33 32 88 fax : 01 49 41 21 15 Dr J. FRRR Dr P. ASSS


Try with this regex expression, I hope the “fax” text will there always.

(?<=tél :|tél:\s).*?(?=fax)

it’s working fine for me @abdel

could you give me the link to the regex tester?

also i had tryed in the c#:

System.Text.RegularExpressions.Regex.Match(item, @"(?<="+row[8]+":|"+row[0]+" :).[0-9\s0-9\W]").Value;

but there is an error: unrecognized escape sequence

HI @abdel,

please refer below URL for testing purpose


You haven’t closed the first “(” braces correctly… we can see two open “(” but only one “)”.


i know that it is not a c# forim but i got the Following error:
: 'Impossible to cast a ‘System.DBNull’ object in ‘System.String’ type

when running the code:

static void Main(string args)
DataTable dtexcel = new DataTable();
Console.WriteLine(“Hello world”);
string PathFolder = “---------” ;
foreach (string file in Directory.EnumerateFiles(PathFolder, “*.txt”))
string labphone= null;
string labname = null;
string Analysisdate= null;

            dtexcel = exceldata("-------.xlsx");

            string[] splitted;
            List<string> List = new List<string>();
            string text = System.IO.File.ReadAllText(file);
            splitted = text.Split('\r');

            foreach (string item in splitted)

                foreach (DataRow row in dtexcel.Rows)
                    if (item.Contains((string)row[8]))
                        Console.WriteLine("row" + row[8]);
                        labphone = System.Text.RegularExpressions.Regex.Match(item, @"(?<=l:|l :).[0-9\s0-9\W]*").Value;


            string extractedlabphone = List.First();
            Console.WriteLine("labphone" + extractedlabphone);
            //Fin d'extraction de télèphone
            foreach (string item in splitted)

                foreach (DataRow row in dtexcel.Rows)
                    Console.WriteLine("Row(0)" + row[0]);
                    if (item.Contains((string)row[0]))

                        labname = item;

            Console.WriteLine("labname" +labname);

            Console.WriteLine("Press any key to exit.");


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