$re = '/\bError importing username: (\d+), primary email: ([^\s@]+@[^\s@,]+)/';
$str = 'string error_message= "{\\"2705\\":\\"Error importing username: 3167763, primary email: pkumar194@google.com, error: User already exists but Email does not match: pkumar194@googlee.com vs pkumar193@google.co.in\\",\\"10001\\":\\"Error importing username: 3195330, primary email: alejandra.mejia@google.com, error: User already exists but Email does not match: alejandra.mejia@google.com vs alejandra.mejia@googlee.com\\"}";
';
preg_match_all($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