[SOLVED] Extractine quoted string from a string

[Mark Baker]

I'm looking for a regular expression that will extract a string from a variable: beginning at the first character and demarked by double quotes at the beginning and end, except that double quotes may exist within the quoted string, where they are escaped by duplicating the double quote ("")

 

The code below shows my current efforts, with some test data, and the expected result:

function testString($string) {
echo 'Test Value is '.$string.'<br />';
$ex = preg_match('/^(\".*([^\"]\"))/i', $string, $match);
if ($ex) {
	print_r($match);
	echo '<br />';
} else {
	echo 'No match found<br />';
}
}

$testData = '"Hello"';
testString($testData);
echo '<b>Expected: </b>"Hello"<br /><br />';

$testData = 'Hello"Goodbye"';
testString($testData);
echo '<b>Expected: </b>No match found<br /><br />';

$testData = '"Hello';
testString($testData);
echo '<b>Expected: </b>No match found<br /><br />';

$testData = '"Hello"Goodbye';
testString($testData);
echo '<b>Expected: </b>"Hello"<br /><br />';

$testData = '"Hello","Goodbye"';
testString($testData);
echo '<b>Expected: </b>"Hello"<br /><br />';

$testData = '"Hello""Goodbye"';
testString($testData);
echo '<b>Expected: </b>"Hello""Goodbye"<br /><br />';

$testData = '"Hel""lo","Goodbye"';
testString($testData);
echo '<b>Expected: </b>"Hel""lo"<br /><br />';

$testData = '"Hello","Good""bye"';
testString($testData);
echo '<b>Expected: </b>"Hello"<br /><br />';

$testData = '"Hel""lo""Good""bye"';
testString($testData);
echo '<b>Expected: </b>"Hel""lo""Good""bye"<br /><br />';

$testData = '"Hello"Goodbye"Hello"';
testString($testData);
echo '<b>Expected: </b>"Hello"<br /><br />';

$testData = '"Hel""lo"Goodbye';
testString($testData);
echo '<b>Expected: </b>"Hel""lo"<br /><br />';

$testData = '"Hel""lo"Goodbye"He""llo"';
testString($testData);
echo '<b>Expected: </b>"Hel""lo"<br /><br />';

 

[.josh]

preg_match('~^"(?:[^"]|"")*"~',$string,$match);

 

edited to add a ^ to the beginning of the pattern; didn't notice you wanted it to only match if its at the beginning.

[Mark Baker]

Thanks Crayon Violent

That's giving me exactly what I need with the test data I'm currently using. I'll test it in the wild with real data, but looks good.