Question

assuming that you have a string with an arbitrary number of lines, each of which follows a pattern such as the one illustrated below,

 Line 498:          [Badsds()]
 Line 499:          protected override void Something() {
 Line 500:              base.Something();

What’s the regular expression that will capture the text after “Line \d+:\s*”?

Answer 1

If you are using c# you can do

List<string> lstMatch=Regex.Matches(input,@"(?<=^\s*Line \d+:)(.*)$",RegexOptions.IgnoreCase|RegexOptions.Multiline)
                           .Cast<Match>()
                           .Select(x=>x.Value)
                           .ToList();

OR

List<string> lstMatch=Regex.Matches(input,@"^\s*Line \d+:\s*(.*)$",RegexOptions.IgnoreCase|RegexOptions.Multiline)
                               .Cast<Match>()
                               .Select(x=>x.Groups[1].Value)
                               .ToList();

If you want to avoid reading all lines at once

foreach (string line in File.ReadLines(fileLocation))
    {
       Regex.Match(line,@"^\s*Line \d+:\s*(.*)$",RegexOptions.IgnoreCase).Groups[1].Value;
    }