Regex.Matches c# double quotes

Question

I got this code below that works for single quotes. it finds all the words between the single quotes. but how would I modify the regex to work with double quotes?

keywords is coming from a form post

so

keywords = 'peace "this world" would be "and then" some'


    // Match all quoted fields
    MatchCollection col = Regex.Matches(keywords, @"'(.*?)'");

    // Copy groups to a string[] array
    string[] fields = new string[col.Count];
    for (int i = 0; i < fields.Length; i++)
    {
        fields[i] = col[i].Groups[1].Value; // (Index 1 is the first group)
    }// Match all quoted fields
    MatchCollection col = Regex.Matches(keywords, @"'(.*?)'");

    // Copy groups to a string[] array
    string[] fields = new string[col.Count];
    for (int i = 0; i < fields.Length; i++)
    {
        fields[i] = col[i].Groups[1].Value; // (Index 1 is the first group)
    }

Wouldn't it work to put the quotes in the string? @-strings use "" instead of \" for quotes. `@"""(.*?)"""` — Kendall Frey, Feb 03 '12 at 18:01

score 26 · Accepted Answer · answered Feb 03 '12 at 18:01

26

You would simply replace the ' with \" and remove the literal to reconstruct it properly.

MatchCollection col = Regex.Matches(keywords, "\\\"(.*?)\\\"");

answered Feb 03 '12 at 18:01

Joel Etherton

37,325
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No need to escape `"` in regex. – Kirill Polishchuk Feb 03 '12 at 18:04
prefect. and if I wanted to include the quotes in the string? – user713813 Feb 03 '12 at 18:07
@user713813: Move the brackets (as well as the _nongreedy_ mark) to the respective ends of the string. – Nuffin Feb 03 '12 at 18:15
According to https://regex101.com/ it's necessary to use `""` in C#/.NET (two consecutive double quotes) to match a single double quote. Unlike Python for instance where you'd simply escape the double quote with a backslash. – domjancik Jul 01 '23 at 15:22
Thanks for that modernization update @domjancik. When this was answered back in 2012, the backslash escape character was the preferred method. I think at the time the double quote only worked in VB.Net, and I could be wrong about that. – Joel Etherton Jul 02 '23 at 17:11

score 13 · Answer 2 · answered Feb 03 '12 at 18:01

The exact same, but with double quotes in place of single quotes. Double quotes aren't special in a regex pattern. But I usually add something to make sure I'm not spanning accross multiple quoted strings in a single match, and to accomodate double-double quote escapes:

string pattern = @"""([^""]|"""")*""";
// or (same thing):
string pattern = "\"(^\"|\"\")*\"";

Which translates to the literal string

"(^"|"")*"

score 7 · Answer 3 · answered Feb 03 '12 at 18:01

7

Use this regex:

"(.*?)"

or

"([^"]*)"

In C#:

var pattern = "\"(.*?)\"";

or

var pattern = "\"([^\"]*)\"";

answered Feb 03 '12 at 18:01

Kirill Polishchuk

54,804
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score 6 · Answer 4 · answered Feb 03 '12 at 19:42

Do you want to match " or ' ?

in which case you might want to do something like this:

[Test]
public void Test()
{
    string input = "peace \"this world\" would be 'and then' some";
    MatchCollection matches = Regex.Matches(input, @"(?<=([\'\""])).*?(?=\1)");
    Assert.AreEqual("this world", matches[0].Value);
    Assert.AreEqual("and then", matches[1].Value);
}

Regex.Matches c# double quotes

4 Answers4

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