Question

In C++, we can define a custom locale that enables stream object to ignore non-digits in the file, and reads only the integers.

Can we do something similar? How can we efficiently read only integers from a text file? Does C# stream object use locale? If yes, can we define custom locale that we can use with stream object so as to ignore unwanted characters while reading the file?

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Here is one example in C++ which efficiently counts frequency of words in a text file:

Elegant ways to count the frequency of words in a file

Answer 1

My proposal:

            public void ReadJustNumbers()
            {
                Regex r = new Regex(@"\d+"); 
                using (var sr = new StreamReader("xxx"))
                {
                    string line;
                    while (null != (line=sr.ReadLine()))
                    {
                        foreach (Match m in r.Matches(line))
                        {
                            Console.WriteLine(m.Value);
                        }
                    }
                }
            }

where xxx is the file name, obviously you will use the matching digit in a more elegant way than dumping on the console 😉