Easiest way to split a string on newlines in .NET?

Question

I need to split a string into newlines in .NET and the only way I know of to split strings is with the Split method. However that will not allow me to (easily) split on a ne

Answer 1

What about using a StringReader?

using (System.IO.StringReader reader = new System.IO.StringReader(input)) {
    string line = reader.ReadLine();
}

Answer 2

I'm currently using this function (based on other answers) in VB.NET:

Private Shared Function SplitLines(text As String) As String()
    Return text.Split({Environment.NewLine, vbCrLf, vbLf}, StringSplitOptions.None)
End Function

It tries to split on the platform-local newline first, and then falls back to each possible newline.

I've only needed this inside one class so far. If that changes, I will probably make this Public and move it to a utility class, and maybe even make it an extension method.

Here's how to join the lines back up, for good measure:

Private Shared Function JoinLines(lines As IEnumerable(Of String)) As String
    Return String.Join(Environment.NewLine, lines)
End Function

Answer 3

Regex is also an option:

    private string[] SplitStringByLineFeed(string inpString)
    {
        string[] locResult = Regex.Split(inpString, "[\r\n]+");
        return locResult;
    }

Answer 4

Try to avoid using string.Split for a general solution, because you'll use more memory everywhere you use the function -- the original string, and the split copy, both in memory. Trust me that this can be one hell of a problem when you start to scale -- run a 32-bit batch-processing app processing 100MB documents, and you'll crap out at eight concurrent threads. Not that I've been there before...

Instead, use an iterator like this;

    public static IEnumerable<string> SplitToLines(this string input)
    {
        if (input == null)
        {
            yield break;
        }

        using (System.IO.StringReader reader = new System.IO.StringReader(input))
        {
            string line;
            while( (line = reader.ReadLine()) != null)
            {
                yield return line;
            }
        }
    }

This will allow you to do a more memory efficient loop around your data;

foreach(var line in document.SplitToLines()) 
{
    // one line at a time...
}

Of course, if you want it all in memory, you can do this;

var allTheLines = document.SplitToLines.ToArray();

Answer 5

string[] lines = text.Split(
  Environment.NewLine.ToCharArray(), 
  StringSplitOptions.RemoveEmptyStrings);

The RemoveEmptyStrings option will make sure you don't have empty entries due to \n following a \r

(Edit to reflect comments:) Note that it will also discard genuine empty lines in the text. This is usually what I want but it might not be your requirement.

Answer 6

You should be able to split your string pretty easily, like so:

aString.Split(Environment.NewLine.ToCharArray());