我有两个变量：
$keystr = 'plant,fruit,exotic';
$value='kiwi';
如何创建关联数组？
$arr = ('plant'=>array('fruit'=>array('exotic'=>'kivi')));
$keystr = 'plant,fruit,exotic';
$value='kiwi';
$arr = array();
$current = &$arr;
$keys = explode(',', $keystr);
foreach($keys as $key) {
$current[$key] = array();
$current = &$current[$key];
}
$current = $value;
unset($current);
var_dump($arr);
请参阅http://ideone.com/YiMIRb用于演示