C#: Looping through lines of multiline string

Question

What is a good way to loop through each line of a multiline string without using much more memory (for example without splitting it into an array)?

Answer 1

I suggest using a combination of StringReader and my LineReader class, which is part of MiscUtil but also available in this StackOverflow answer - you can easily copy just that class into your own utility project. You'd use it like this:

string text = @"First line second line third line";  foreach (string line in new LineReader(() => new StringReader(text))) {     Console.WriteLine(line); } 

Looping over all the lines in a body of string data (whether that's a file or whatever) is so common that it shouldn't require the calling code to be testing for null etc :) Having said that, if you do want to do a manual loop, this is the form that I typically prefer over Fredrik's:

using (StringReader reader = new StringReader(input)) {     string line;     while ((line = reader.ReadLine()) != null)     {         // Do something with the line     } } 

This way you only have to test for nullity once, and you don't have to think about a do/while loop either (which for some reason always takes me more effort to read than a straight while loop).