Demystifying the C# Yield-Return Mechanism: Listing 2.
The FetchNextLine method.
static IEnumerable<string> FetchNextLine(string fileName)
{
StreamReader sr = new StreamReader(fileName);
string line = "";
string[] tokens = null;
while ((line = sr.ReadLine()) != null)
{
if (line.StartsWith("d@") == true)
yield return line;
else if (line.StartsWith("a@") == true) {
string s = line.Replace('a', 'd');
line = sr.ReadLine(); // advance to next line
tokens = line.Split('@');
s += tokens[1];
yield return s;
}
}
sr.Close();
}
About the Author
Dr. James McCaffrey directs the data science and research efforts at Quaetrix, a data analytics company located near Redmond, Washington. Before joining Quaetrix, James was a senior research engineer at Microsoft. James can be reached at [email protected].