Help with regular expressions

Question

Hello, I am new to c#. I need to write a method that takes a log file created by a compilation output and figures out the number of errors and warnings. I need to scan each line of the log and find the following match: x error(s), y warning(s)

Examples of this patterns are:

 Compile complete -- 1 errors, 213 warnings

 6>Process_Math - 3 error(s), 1 warning(s)
 24>Process_Math - 1 error(s), 0 warning(s)

How can I write the algorithm that finds that pattern and extract x and y from the line? Thanks Tony

Answer 1

Here is a small example:

using System;
using System.Text.RegularExpressions;

class Program
{
    static void Main()
    {
     String input = @"Compile complete -- 1 errors, 213 warnings

        6>Process_Math - 3 error(s), 1 warning(s)
        24>Process_Math - 1 error(s), 0 warning(s)";

     Regex regex = new Regex(@"(\d+)\serrors?,\s(\d+)\swarnings?",
      RegexOptions.Compiled |
      RegexOptions.CultureInvariant |
      RegexOptions.IgnoreCase |
      RegexOptions.Multiline);

     Match match = regex.Match(input);

     if (match.Success)
     {
      Console.WriteLine("errors: " + match.Groups[1].Value);
      Console.WriteLine("warnings: " + match.Groups[2].Value);
     }
    }
}

This will grab the errors and warnings from the first line, not the subsequent ones.

Here is a commented version of the regular expression to help explain how it works:

(\d+)     # capture any digit, one or more times
\s        # match a single whitespace character
errors?,  # match the string "error" or "errors" followed by a comma
\s        # match a single whitespace character
(\d+)     # capture any digit, one or more times
\s        # match a single whitespace character
warnings? # match the string "warning" or "warnings"

Answer 2

int errors = 0;
int warnings = 0;

Regex regexObj = new Regex(@"(?<errors>\d+) error\(s\), (?<warnings>\d+) warning\(s\)", RegexOptions.Multiline);
Match matchResults = regexObj.Match(input);
while (matchResults.Success) 
{
 errors = errors + Convert.ToInt16(matchResults.Groups["errors"].Value);
 warnings = warnings + Convert.ToInt16(matchResults.Groups["warnings"].Value);
 matchResults = matchResults.NextMatch;
}

Answer 3

Having never done any work in C#, I can only advise on the regular expression itself:

^\d*>?(Compile complete|Process_Math) -{1,2} (\d+) error\(?s\)?, (\d+) warning\(?s\)?

This matches a string that might begin with a number, captures the leading text into the first capturing group, and captures the number of errors & warnings into the second and third capturing groups, respectively.

Answer 4

This example works well for errors:

using System;
using System.Text.RegularExpressions;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            string compilationOutput =
                "Compile complete -- 1 errors, 213 warnings" +
                "Compile complete -- 2 errors, 213 warnings" +
                "Compile complete -- 3 errors, 213 warnings" +
                "Compile complete -- 4 errors, 213 warnings";

            string pattern = @"(\d+) error(:?s)?";

            MatchCollection results = Regex.Matches(compilationOutput, pattern, RegexOptions.IgnoreCase);

            int errors = 0;
            foreach (Match m in results)
            {
                int error;
                if (int.TryParse(m.Groups[1].Value, out error))
                {
                    errors += error;
                }
            }
        }
    }
}