PHP uses recursion to change all the key names in a multidimensional array to uppercase or lowercase

$arr  = array (   ' A '  =>  ' a ',   ' B '  =>  ' B ',   ' C '  => array (      ' e '  =>  ' F ',  ' G '  => array (      ' H '  =>  ' i ', ' j '  =>  ' o ',  ',    ' abc ' = Array (       ' R '  =>  ' 222 ',   ),  ); Function array_case (& $array,  $case =case_lower)  {   $array  = array_change _key_case ($array,  $case);    foreach  ($array  as  $key  => $ Value)  {        if  ( is_array ($value)  )  {             array_case ($array [$key],  $case);         }    }}array_case ($arr, CASE_LOWER);p Rint_r ($arr);

I haven't thought about it for a long time.

Finally still rely on the great Baidu, Baidu really powerful AH.

The main use of the inside of the method of assignment, that is, this place is difficult.

PHP uses recursion to change all the key names in a multidimensional array to uppercase or lowercase