Array length is the same, how to change the key name of an array into the key value of the second array

Array length is the same, how to change the key name of an array into the key value of the second array.
For example, I have $aa ... $bb

$aa =array ("0" = "CD", "1" = "Udd", "2" = "DSD");
$BB =array ("0" = 13ds, "1" = "TDFESTSDFA1", "2" = "1122sdfdsasdf33abc");
Change the key name of the $AA array to the key value of the second array $bb.

How to form the following array ￥cc.

$CC =array ("cd" = 13ds, "udd" = "tdfestsdfa1", "DSD" = "1122sdfdsasdf33abc");

Please be expert in pointing.
------to solve the idea----------------------

$AA = Array ("0" = "CD", "1" = "Udd", "2" = "DSD");
$BB = Array ("0" = "13ds", "1" = "TDFESTSDFA1", "2" = "1122sdfdsasdf33abc");
$CC = Array_combine ($aa, $BB);
Print_r ($CC);

$AA = Array ("0" = "CD", "1" = "Udd", "2" = "DSD");
$BB = Array ("0" = "13ds", "1" = "TDFESTSDFA1", "2" = "1122sdfdsasdf33abc");
$CC = Array_combine ($aa, $BB);
Print_r ($CC);

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