PHP multiple new lines

Question

I\'m a little stuck. How do I remove multiple newlines which are in a row with one newline. There could be anything up to 20 newlines next to each other. For example

Answer 1

$str = 'James said hello\n\n\n\n Test\n Test two\n\n';
echo preg_replace('{(\\\n)\1+}','$1',$str);