取出关联数组的key值，可用 array_keys()取出;
<?php
$a=array("Volvo"=>"XC90","BMW"=>"X5","Toyota"=>"Highlander");
print_r(array_keys($a));
?>
输出结果
Array ( [0] => Volvo [1] => BMW [2] => Toyota )
取出关联数组的values值，可用 array_values()取出;
<?php
$a=array("Name"=>"Bill","Age"=>"60","Country"=>"USA");
print_r(array_values($a));
?>
输出结果
Array ( [0] => Bill [1] => 60 [2] => USA )