如何删除特定元素表单数组

Array
(
    [userid] => 1
    [alias] => rahul
    [firstname] => rahul
    [lastname] => Khan2
    [password] => Ý2jr™``¢(E]_Ø=^
    [email] => salman@gmail.com
    [url] => 4cfe07dbf35d6.jpg
    [avatar_url] => 4cfe07efd2e1c.jpg
    [thumb] => 4cfe07ebc8955.jpg
    [crop_url] => 4cfe07dbf35d6.jpg
    [crop_position] => [100,100,200,200]
    [updatedon] => 0000-00-00 00:00:00
    [createdon] => 0000-00-00 00:00:00
)