How to find a nested quotation with a regular expression?

"Hello my name 开发者_C百科is "Joe" and I'm 13."

I want the regex to print out "Joe" only, can this be done?

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You didn't provide the platform you're using for this regex but here is one way using php:

$content='Hello my name is "Joe" and I\'m 13.';
preg_match('/"[^"]*"/', $content, $m);
print_r($m);

Update:

As per the comment below here is the code that OP is probably looking for:

$content='foo "Hello my name is "Joe" and I\'m 13." bar';
preg_match('/"[^"]*"([^"]*)"/', $content, $m);
var_dump($m[1]);

OUTPUT

string(3) "Joe"

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A regular expression that will find a quoted string within another quoted string:

/\".*?\"(.*)\".*?\"/

http://rubular.com/r/L8dMtNZxP5

The interior quoted string will be in \1.

Now, if you want a more complex nesting structure, you'll need additional logic to account for that. The linked site may help you generate any further logic.

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(?<!"[^"]*)"([^"]+)"

Consider this string (with \ escaped quotes): string test = "\"Hello my name is \"Joe\" and I'm 13.\"";

That expression will match "Joe" and the first capture will be Joe. I couldn't tell which you were trying to get from your question.

In C#:

var match = Regex.Match(mystring,
            "(?<!\"[^\"]*)\"([^\"]+)\"",
            RegexOptions.IgnoreCase | RegexOptions.IgnorePatternWhitespace);
Console.WriteLine(match.Value);            // "Joe"
Console.WriteLine(match.Groups[1].Value);  // Joe

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Here's one fairly generic way to go about finding a single word inside double quotes, using Python's re module.

>>> import re
>>> string = '''"Hello my name is "Joe" and I'm 13"'''
>>> re.compile('"\w+"').search(string)
<_sre.SRE_Match object at 0xb73dc720>
>>> _.group()
'"Joe"'