PHP 逆配列および順列配列のキーと値の詳細な説明

array array_reverse(array array [, boolean preserve_keys])

$states = array("Delaware" , "Pennsylvania" , "New Jersey");print_r(array_reverse($states));// Array ( [0] => New Jersey [1] => Pennsylvania [2] => Delaware )

$states = array("Delaware" , "Pennsylvania" , "New Jersey");print_r(array_reverse($states, 1));// Array ( [2] => New Jersey [1] => Pennsylvania [0] => Delaware )

array array_flip(array array)

$state = array("Delaware" ,"Pennsylvania" , "New Jersey");$state = array_flip($state);print_r($state);

Array ( [Delaware] => 0 [Pennsylvania].=> 1 [New Jersey] => 2 )