[ACCEPTED]-How to take only first line from the multiline text-regex

Accepted answer
Score: 40

If you just need the first line, you can 6 do it without using a regex like this

var firstline = test.Substring(0, test.IndexOf(Environment.NewLine));

As 5 much as I like regexs, you don't really 4 need them for everything, so unless this 3 is part of some larger regex exercise, I 2 would go for the simpler solution in this 1 case.

Score: 11
string test = @"just take this first line
even there is 
some more
lines here";

Match m = Regex.Match(test, "^(.*)", RegexOptions.Multiline);
if (m.Success)

. is often touted to match any character, while 5 this isn't totally true. . matches any character 4 only if you use the RegexOptions.Singleline option. Without this 3 option, it matches any character except 2 for '\n' (end of line).

That said, a better option is likely to be:

string test = @"just take this first line
even there is 
some more
lines here";

string firstLine = test.Split(new string[] {Environment.NewLine}, StringSplitOptions.None)[0];

And better yet, is Brian 1 Rasmussen's version:

string firstline = test.Substring(0, test.IndexOf(Environment.NewLine));
Score: 1

Try this one:

Match m = Regex.Match(test, @".*\n", RegexOptions.Multiline);


Score: 0

This kind of line replaces rest of text 3 after linefeed with empty string.

test = Regex.Replace(test, "(\n.*)$", "", RegexOptions.Singleline);

This will 2 work also properly if string does not have 1 linefeed - then no replacement will be done.

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