How to match different scenarios with regex in c# and groups-CodePudding

I want to match these different scenarios with a regex pattern. Mainly delimiter is #:

1234-1111-234.011#333 => [id = 1234-1111-234.011 and code =333]
whatever text before 1234-1111-234.011#333 => [textb=whatever text before, id = 1234-1111-234.011 , code =333, texta="]
1234-1111-234.011#333 whatever text after => [ textb="" id = 1234-1111-234.011 ,code =333 , texta=whatever text after]
Text can be both at the beginning or the end
In every case code can contain also a postfix letter W like 1234-1111-234.011#333W => code=333E
textb = text with length maximum 15 characters. Only letters and numbers.
id = 17 character long with this format XXXX-XXXX-XXX.XXX code - 3 or 4 character long based on W letter is presenting or not
texta = text with length maximum 15 characters. Only letters and
numbers.

I am trying to match these scenarios with this piece of code and groups

pattern ="
    ?(<textb>[\w\s]{15})#
    ?(<id>[\d\s]{17,17})#
    (?<code>([A-Z]{0,1}\d{2,3}))
    (?<wo>[W]{1})
    ?(<texta>[\w\s]{15})"

and

  var textb = Regex.Match(mytext, pattern).Groups["textb"].Value;    
  var id= Regex.Match(mytext, pattern).Groups["id"].Value;
  var code= Regex.Match(mytext, pattern).Groups["code"].Value;
  var wo= Regex.Match(mytext, pattern).Groups["wo"].Value;
  var texta= Regex.Match(mytext, pattern).Groups["texta"].Value;

A full example is "This is before text 234-1111-234.011#333E This is next text"
Not matching at all.

CodePudding user response：

You could do it with one regular expression and then use Groups to get the parts you need.

void Main()
{
    var input = "Before text 1234-1111-234.011#333E After text";
    var pattern = @"(?<btext>[\w ]{0,15})(?<id>[\d\-\.]{17})#(?<code>[\d]{2,3})(?<wo>[A-Z]?)(?<atext>[\w ]{0,15})";
    
    var matches = Regex.Match(input, pattern);
    
    var btext = matches.Groups["btext"];
    var wo = matches.Groups["wo"];
    
    Console.WriteLine(btext.Value);
    Console.WriteLine(wo.Value);

    // etc.
}

(?<btext>[\w ]{0,15}) // Match letters, numbers and spaces, minimum 0 chars, maximum 15 chars
(?<id>[\d\-\.]{17})   // match numbers, '-' and '.'. Must be 17 chars
#                     // Match pound sign
(?<code>[\d]{2,3})    // Match numbers 2 or 3 chars long
(?<wo>[A-Z]?)         // Match optional letter after code
(?<atext>[\w ]{0,15}) // Match letters, numbers and spaces, minimum 0 chars, maximum 15 chars