PHP去除連續(xù)的空格和換行符

$str="i   am    a     book\n\n\n\n\nmoth";

//去除所有的空格和換行符

echo preg_replace("/[\s]{2,}/"," ",$str);

//去除多余的空格和換行符，只保留一個

echo preg_replace("/([\s]{2,})/","\\1",$str);