$re = '/(?=.*[+-]\d+\.\d+).*([+-]\d+\.\d+).*|(.*)/m';
$str = 'Stephane Robert (+1.5 Sets)
Stephane Robert (-1.5 Sets)
Philipp Kohlschreiber
Philipp Kohlschreiber (-1.5 Sets)
Philipp Kohlschreiber (+1.5 Sets)
Player Names (n)
Another Player-Player';
$subst = "\1";
$result = preg_replace($re, $subst, $str);
echo "The result of the substitution is ".$result;
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