Question

I have a text file named C:/test.txt:

1 2 3 4
5 6

I want to read every number in this file using StreamReader.

How can I do that?

Answer 1

Do you really need to use a StreamReader to do this?

IEnumerable<int> numbers =
    Regex.Split(File.ReadAllText(@"c:\test.txt"), @"\D+").Select(int.Parse);

(Obviously if it’s impractical to read the entire file in one hit then you’ll need to stream it, but if you’re able to use File.ReadAllText then that’s the way to do it, in my opinion.)

For completeness, here’s a streaming version:

public IEnumerable<int> GetNumbers(string fileName)
{
    using (StreamReader sr = File.OpenText(fileName))
    {
        string line;
        while ((line = sr.ReadLine()) != null)
        {
            foreach (string item in Regex.Split(line, @"\D+"))
            {
                yield return int.Parse(item);
            }
        }
    }
}