C＃比较两个文件的正则表达式问题

Question

what I'm trying to do is open a huge list of files (about 40k records, and match them on a line in a file that contains 2 millions records. And if my line from file A matches a line in file B write out that line.

File A contains a bunch of files without extensions and file B contains full file paths including extensions.

i'm using this but i cant get it to go...

string alphaFilePath = (@"C:\\Documents and Settings\\g\\Desktop\\Arrp\\Find\\natst_ready.txt");

            List<string> alphaFileContent = new List<string>();

            using (FileStream fs = new FileStream(alphaFilePath, FileMode.Open))
            using (StreamReader rdr = new StreamReader(fs))
            {
                while (!rdr.EndOfStream)
                {
                    alphaFileContent.Add(rdr.ReadLine());
                }
            }

            string betaFilePath = @"C:\Documents and Settings\g\Desktop\Arryup\Find\eble.txt";

            StringBuilder sb = new StringBuilder();

            using (FileStream fs = new FileStream(betaFilePath, FileMode.Open))
            using (StreamReader rdr = new StreamReader(fs))
            {
                while (!rdr.EndOfStream)
                {
                    string betaFileLine = rdr.ReadLine();
string matchup = Regex.Match(alphaFileContent, @"(\\)(\\)(\\)(\\)(\\)(\\)(\\)(\\)(.*)(\.)").Groups[9].Value;
                    if (alphaFileContent.Equals(matchup))
                    {
                        File.AppendAllText(@"C:\array_tech.txt", betaFileLine);
                    }
                }
            }

This doesnt work because the alphafilecontent is a single line only and i'm having a hard time figuring out how to get my regex to work on the file that contains all the file paths (Betafilepath)

here is a sample of the beta file path.

C:\\arres_i\\Grn\\Ora\\SEC\\DBZ_EX1\\Nes\\001\\DZO-EX00001.txt

Here is the line i'm trying to compare from my alpha DZO-EX00001

Answer 1

Use System.IO.Path.GetFileNameWithoutExtension instead of a regular expression.

    static void Compare(string alpha, string beta)
    {
        HashSet<string> alphaContent = new HashSet<string>();
        StreamReader reader = new StreamReader(alpha);
        while (!reader.EndOfStream)
            alphaContent.Add(reader.ReadLine());
        reader.Close();

        reader = new StreamReader(beta);
        while (!reader.EndOfStream)
        {
            string fullpath = reader.ReadLine();
            string filename = Path.GetFileNameWithoutExtension(fullpath);
            if (alphaContent.Contains(filename))
            {
                File.AppendAllText(@"C:\array_tech.txt", fullpath);
            }
        }
        reader.Close();
    }

Answer 2

So, you read in all the lines in beta, and have the whole thing stored in a string, beta .

Next, you read a line from alpha and have DZO-EX00001 stored in a string, alpha .

var pattern = @"^.*" + alpha + ".*$";
var match = Regex.Match(beta, pattern, RegexOptions.Multiline);

if(match.Success)
{
   string filepath = match.Value;
   // do stuff
}

You need to load all of the lines from beta first. Then you can check each line from alpha against it.

You must specify RegexOptions.Multiline to check against all the lines in beta (so that the ^ and $ will match at each line instead of at the beginning and end of the whole string.

The pattern can be expanded if you need to be more specific; as is, it just gets the first line that contains the filename.