PHP basic problem Two-dimensional array summation!

Array:
$a = Array ("A" and "AA", "A1" =>1, "A2" =>1), Array ("a" = "BB", "A1" =>2, "A2" =>2), Array ("a" and "=" cc "," A1 "=>3," A2 "=>3), Array (" a "+ =" AA "," A1 "=>1," A2 "=>1), Array (" a "=" BB "," A1 "=>5," A2 "=>5))
Sum of elements with the same key value as the first one
Results
$r = Array ("A" and "AA", "A1" =>2, "A2" =>2), Array ("a" = "BB", "A1" =>7, "A2" =>7), Array ("a" and "=" cc "," A1 "=>3," A2 "=>3));

Reply to discussion (solution)

$a = Array (  "a" and "AA", "a1" = 1, "A2" and "= 1"),  Array ("A" and "BB", "A1" and "2", "a2" = 2), C2/>array ("A" and "CC", "a1" = 3, "A2" and "= 3"),  Array ("A" and "" AA "," a1 "= 1," a2 "= 1),  array (" a "=" BB "," a1 "= 5," a2 "= 5), $res = Array (); foreach ($a as $r) {  if (! Isset ($res [$r [' a ']]) $res [$r [' a ']] = $r;  else {    $res [$r [' A ']][' A1 '] + = $r [' A1 '];    $res [$r [' A ']][' A2 '] + = $r [' A2 '];}  Print_r (Array_values ($res));

Array (    [0] = = Array        (            [A] = AA            [a1] = 2            [a2] = 2        )    [1] = = ARRAY
   (            [A] = BB            [a1] = 7            [A2] + 7        )    [2] = = Array        (            [a] + = CC            [A1] = 3            [A2] + 3        ))

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