CODEWITHSUNDEEP
c#regex
m_beta
m_beta

Reputation: 162

Searching for string pattern using RegEx matching C#

I wish to find a match of *|END_OF_PARAM|ABC_XYZ_123.txt in a given string (meaning string starts with anything but containing |END_OF_PARAM| followed by a filename(which has alphabets, numbers, _ ,-) and ending in ".txt").

eg:

string input = "| AB|3|20200914-01|5| | |END_OF_PARAM|ABC-XYZ-20200914-PIA-03_05_20200914132900.txt";
string pattern = @"*/([A-Za-z0-9\-]+)\.txt$"   // What exactly should go here?
Match match = Regex.Match(input, @"*/([A-Za-z0-9\-]+)\.txt$",
        RegexOptions.IgnoreCase);

if (match.Success)
{
    Console.WriteLine("Match!"));
}

Output I need is ABC-XYZ-20200914-PIA-03_05_20200914132900.txt

ps : Somelines end with |END_OF_PARAM| and don't have the filename after them, such lines should be ignored.

I don't know much of RegEx, tried to learn it and get my task done but it's taking longer than expected. Let me know if any additional data is needed. Thank you.

Upvotes: 0

Views: 86

Answers (1)

The fourth bird
The fourth bird

Reputation: 163632

The character class is missing an underscore to match the filename in total. If you want to include the |END_OF_PARAM| part you should add it to the match.

To differentiate the filename from the total match, you could capturing it in a group and get that value.

^.*\|END_OF_PARAM\|([A-Za-z0-9_-]+\.txt)$

Explanation

  • ^ Start of string
  • .* Match any char except a newline 0+ times
  • \|END_OF_PARAM\| Match END_OF_PARAM between a pipe at the left and right
  • ( Capture group 1
    • [A-Za-z0-9_-]+\.txt Match 1+ times any of the listed chars followed by .txt
  • ) Capture group 1
  • $ End of string

Regex demo | C# demo

enter image description here

string input = "| AB|3|20200914-01|5| | |END_OF_PARAM|ABC-XYZ-20200914-PIA-03_05_20200914132900.txt";
string pattern = @"^.*\|END_OF_PARAM\|([A-Za-z0-9_-]+\.txt)$";
Match match = Regex.Match(input, pattern);

if (match.Success)
{
    Console.WriteLine(match.Groups[1]);
}

Output

ABC-XYZ-20200914-PIA-03_05_20200914132900.txt

Upvotes: 2

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