如何使用C＃从.asc文件中的特定位置读取数据

Question

I have .asc file which has 1000's of rows. Each column in row is of the fixed length and separate by one space. I want to read email id column which is started from 296 position and ended at 326 position in a row.

Is there any way to read such data from .asc file?

Answer 1

This might do the trick for you. I am just reading the email ids in the file whatever extension file it might me, may it be txt or asc. Also it doesnt matter if the email address is locating at some other place instead of 296 or 326.

public void ExtractAllEmails()
{
    string datafrmAsc = File.ReadAllText(YourASCFile); //read File 
    Regex emailRegex = new Regex(@"\w+([-+.]\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*", RegexOptions.IgnoreCase);
    MatchCollection emailMatches = emailRegex.Matches(datafrmAsc);
    StringBuilder sb = new StringBuilder();
    foreach (Match emailMatch in emailMatches)
    {
        sb.AppendLine(emailMatch.Value);
    }
    File.WriteAllText(SomeTxtFile, sb.ToString());
}

Answer 2

Assuming that is large text file, you can do something like this:

        List<string> emailsList = new List<string>();
        int startIndex = 295;
        int endIndex = 325;

        using (FileStream stream = File.Open("c:\\test.asc", FileMode.Open))
        using (StreamReader sr = new StreamReader(stream))
        {
                string line = string.Empty;
                while ((line = sr.ReadLine()) != null)
                {
                    emailsList.Add(line.Substring(startIndex, endIndex - startIndex).Trim());
                }

         }