php空变量count与empty
php > $array;
php > echo count($array);
0
php > $array = false;
php > echo count($array);
1
php > $array = null;
php > echo count($array);
0
php > $array = array();
php > echo count($array);
0
php > $array;
php > echo count($array);
0
php > $array = false;
php > echo count($array);
1
php > $array = null;
php > echo count($array);
0
php > $array = array();
php > echo count($array);
0