$filter = "/[,.;\"\'~!@#\$%^&*]()\[\]\{\}\?\/\\!,。;:‘“?()、·……— ]/";
//过滤
$keyword = preg_replace($filter, "", $keyword );
//判断
if( $keyword == "" ) echo "全是标点";
//过滤
$keyword = preg_replace($filter, "", $keyword );
//判断
if( $keyword == "" ) echo "全是标点";
比如说[:punct:]代表任何英文类的标点符号,中文的呢?