Using a Regex to find all instances of a specific string within a document, where a few words within-CodePudding

So I know using a regex to accomplish this task is the way to go, but I am beyond abysmal when it comes to using them.

I have a log document, where in the document will be many instances of such a line:

INFO Example.Services.Controllers.SubscribeController - Beginning Log Subscription for EmployeeID: jdoe RecordID: 111222

There is a lot of other stuff in the log document, like stack traces and what not.

I want to extract each instance of the line above out, but the I am having trouble because the values for "EmployeeID" and "RecordID" change.

CodePudding user response：

Assuming that your employee id is only small characters and record id is numbers only, then the regex to match this line would be (INFO Example\.Services\.Controllers\.SubscribeController - Beginning Log Subscription for EmployeeID: [a-z] RecordID: [0-9]). Sample code to match your regex with your test string is

using System;
using System.Text.RegularExpressions;

public class Example
{
    public static void Main()
    {
        string pattern = @"(INFO Example\.Services\.Controllers\.SubscribeController - Beginning Log Subscription for EmployeeID: [a-z] RecordID: [0-9])";
        string input = @"Test String";
        RegexOptions options = RegexOptions.Multiline;
        
        foreach (Match m in Regex.Matches(input, pattern, options))
        {
            Console.WriteLine("'{0}' found at index {1}.", m.Value, m.Index);
        }
    }
}

If there are more rules to your employee id and record id then you can add them in the regex to fine-tune it. Like, if record id is exactly six characters than your regex would be (INFO Example\.Services\.Controllers\.SubscribeController - Beginning Log Subscription for EmployeeID: [a-z] RecordID: [0-9]{6}). If you want to add condition to employeeid for 20 characters than regex would be (INFO Example\.Services\.Controllers\.SubscribeController - Beginning Log Subscription for EmployeeID: [a-z]{1,20} RecordID: [0-9]{6}). So, Employee can be anywhere between 1 and 20 characters. write [a-zA-Z] if it contains capital letters as well and [a-zA-Z0-9] if it contain alphabets and numbers