$re = '/\'[^\']*\'(*SKIP)(*FAIL)|(?:"(([^"]*`")*[^"]*|[^"]*)")/';
$str = 'The two sentences are \'He said "Hello there"\' and "She said \'goodbye\' and \'another sentence\'"
" `" "
" `" "
" `" `" "
" `" `" `" "
\' " " \'
"string"
" \'xyz\' "
" `" "
" `" `" "
" `" `" `" "
\' \' "should match" \' \'
\' "should not match" \'
';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php