数组中对某项相同的值进行求和计算

$arr = array(15) {  [0]=>  array(9) {    ["lppt"]=>    string(4) "lp1 "    ["fg_type"]=>    string(5) "ecu  "    ["customer_no"]=>    string(4) "a001"    ["etype1"]=>    string(3) "dig"    ["revdegree"]=>    string(2) "s "    ["item1"]=>    float(8810)    ["rs1"]=>    float(5787788.527)    ["item2"]=>    float(8928)    ["rs2"]=>    float(5865309.4176)  }  [1]=>  array(9) {    ["lppt"]=>    string(4) "lp1 "    ["fg_type"]=>    string(3) "ecu"    ["customer_no"]=>    string(4) "a001"    ["etype1"]=>    string(3) "mpi"    ["revdegree"]=>    string(1) "b"    ["item1"]=>    float(0)    ["rs1"]=>    float(0)    ["item2"]=>    float(0)    ["rs2"]=>    float(0)  }  [2]=>  array(9) {    ["lppt"]=>    string(4) "lp1 "    ["fg_type"]=>    string(4) "ecu "    ["customer_no"]=>    string(4) "a001"    ["etype1"]=>    string(3) "mpi"    ["revdegree"]=>    string(2) "s "    ["item1"]=>    float(63485)    ["rs1"]=>    float(23211270.7503)    ["item2"]=>    float(71973)    ["rs2"]=>    float(26689668.0654)  }  [3]=>  array(9) {    ["lppt"]=>    string(4) "lp1 "    ["fg_type"]=>    string(4) "ecu "    ["customer_no"]=>    string(4) "a002"    ["etype1"]=>    string(3) "mpi"    ["revdegree"]=>    string(2) "s "    ["item1"]=>    float(4810)    ["rs1"]=>    float(2329072.60146)    ["item2"]=>    float(5855)    ["rs2"]=>    float(2783605.29921)  }  [4]=>  array(9) {    ["lppt"]=>    string(4) "lp1 "    ["fg_type"]=>    string(5) "ecu  "    ["customer_no"]=>    string(4) "a004"    ["etype1"]=>    string(3) "mpi"    ["revdegree"]=>    string(2) "s "    ["item1"]=>    float(1716)    ["rs1"]=>    float(652004.847)    ["item2"]=>    float(1711)    ["rs2"]=>    float(647801.6757)  }[5]=>  array(9) {    ["lppt"]=>    string(4) "lp2 "    ["fg_type"]=>    string(3) "ecu"    ["customer_no"]=>    string(4) "a001"    ["etype1"]=>    string(3) "mpi"    ["revdegree"]=>    string(1) "b"    ["item1"]=>    float(0)    ["rs1"]=>    float(0)    ["item2"]=>    float(0)    ["rs2"]=>    float(0)  }};

	$arr = array(		array('fg_type'=>'ECU1', 'item1'=>8810, 'rs1'=>5787788.527, 'item2'=>8928, 'rs2'=>5865309.4176),		array('fg_type'=>'ECU1', 'item1'=>0, 'rs1'=>0, 'item2'=>0, 'rs2'=>0),		array('fg_type'=>'ECU2', 'item1'=>63485, 'rs1'=>23211270.7503, 'item2'=>71973, 'rs2'=>26689668.0654),		array('fg_type'=>'ECU2', 'item1'=>4810, 'rs1'=>2329072.60146, 'item2'=>5855, 'rs2'=>2783605.29921),		array('fg_type'=>'ECU3', 'item1'=>1716, 'rs1'=>652004.847, 'item2'=>1711, 'rs2'=>647801.6757),		array('fg_type'=>'ECU3', 'item1'=>0, 'rs1'=>0, 'item2'=>0, 'rs2'=>0),	);		$new_arr = array(); 	for($i=0; $i<count($arr); $i++){		$arr[$i]['sum'] = $arr[$i]['item1'] + $arr[$i]['rs1'] + $arr[$i]['item2'] + $arr[$i]['rs2'];		$new_arr[$arr[$i]['fg_type']] = 0;	}		for($i=0; $i<count($arr); $i++){		if(array_key_exists($arr[$i]['fg_type'], $new_arr)){			$new_arr[$arr[$i]['fg_type']] += $arr[$i]['sum'];		}	}		array_push($arr,$new_arr);		echo '<pre class="brush:php;toolbar:false;">';	print_r($arr);