我正在尝试使用相同的 car_name和edition_num 来计算数组中元素的数量但不同的买家，我需要将总数量放回到数组中，以便将其保存到数组中数据库中。
我遇到的问题是我选择总和的方式。它通过将匹配元素放入quantity数组来工作，除非它遇到一个不匹配的元素，然后它 - ＆gt;
1. runs a loop over the size of the quantity array and sums the total
2. empties array
3. puts the new element into it.
问题出在我的库存循环中，我需要保存的total_sum是我的数组的最后一个索引，但这不起作用：
$inventory[$k-1]['total_buy'] = $buy_sum;
这样做的正确方法是什么？ http://ideone.com/ZjnuRi
<?php
$len = '[{"car_name":"Mazda","edition_num":"Prius","code":"M",
"buyer":"JamesT","used":0,"buy_price":3.877,"buy_quantity":4,
"sell_price":4.175,"sell_quantity":0},
{"car_name":"Mazda","edition_num":"Prius","code":"M",
"buyer":"steveF","used":0,"buy_price":3.879,"buy_quantity":1,
"sell_price":4.174,"sell_quantity":3},
{"car_name":"Mazda","edition_num":"Prius","code":"M",
"buyer":"KirkL","used":0,"buy_price":3.879,"buy_quantity":4,
"sell_price":4.174,"sell_quantity":0},
{"car_name":"Toyota","edition_num":"Prius","code":"U",
"buyer":"JamesT","used":0,"buy_price":0.007,"buy_quantity":2,
"sell_price":0.042,"sell_quantity":2},
{"car_name":"Toyota","edition_num":"Prius","code":"U",
"buyer":"steveF","used":0,"buy_price":0.007,
"buy_quantity":0,"sell_price":0.042,"sell_quantity":4},{"car_name":"Toyota","edition_num":"Prius","code":"U",
"buyer":"KirkL","used":0,"buy_price":0.007,"buy_quantity":-2,
"sell_price":0.042,"sell_quantity":6}]';
$inventory = json_decode($len,true);
$timeNow = date('Y-m-d H:i:s');
$q_c = array();
for($k=0 ; $k < sizeof($inventory); $k++)
{
$buy_sum = 0;
$sell_sum = 0;
if(empty($q_c))
{
$q_c[] =
array('car_name'=>$inventory[$k]['car_name'],
'edition_num' => $inventory[$k]['edition_num'] ,
'buy_quantity' => $inventory[$k]['buy_quantity'] ,
'sell_quantity' => $inventory[$k]['sell_quantity'] ,
'buyer' => $inventory[$k]['buyer']);
}
// set quantity control to the current car if not empty:
//if quantity control not empty put current car into it.
//same car:
else
{
if($inventory[$k]['car_name'] == $q_c[0]['car_name'] && $inventory[$k]['edition_num'] == $q_c[0]['edition_num'])
{
$q_c[] =
array('car_name'=>$inventory[$k]['car_name'],
'edition_num' => $inventory[$k]['edition_num'] ,
'buy_quantity' => $inventory[$k]['buy_quantity'] ,
'sell_quantity' => $inventory[$k]['sell_quantity'] ,
'buyer' => $inventory[$k]['buyer']
);
}
//new : sum total for last car:
else
{
for($i=0; $i < sizeof($q_c); $i++)
{
$buy_qty = $q_c[$i]['buy_quantity'];
$sell_qty = $q_c[$i]['sell_quantity'];
$buy_sum += intval ($buy_qty);
$sell_sum += intval ($sell_qty);
//----THIS LINE DOES NOT WORK ---
$inventory[$k-1]['total_buy'] = $buy_sum;
//----THIS LINE DOES NOT WORK ---
}
//clear out the array
$q_c = array();
//push current car into it:
$q_c[] =
array('car_name'=>$inventory[$k]['car_name'],
'edition_num' => $inventory[$k]['edition_num'] ,
'buy_quantity' => $inventory[$k]['buy_quantity'] ,
'sell_quantity' => $inventory[$k]['sell_quantity'] ,
'buyer' => $inventory[$k]['buyer']
);
}
}
echo '<pre>';
print_r($inventory[$k]);
echo '</pre>';
}
?>
Array
(
[car_name] => Mazda
[edition_num] => Prius
[code] => M
[buyer] => JamesT
[used] => 0
[buy_price] => 3.877
[buy_quantity] => 4
[sell_price] => 4.175
[sell_quantity] => 0
)
Array
(
[car_name] => Mazda
[edition_num] => Prius
[code] => M
[buyer] => steveF
[used] => 0
[buy_price] => 3.879
[buy_quantity] => 1
[sell_price] => 4.174
[sell_quantity] => 3
)
Array
(
[car_name] => Mazda
[edition_num] => Prius
[code] => M
[buyer] => KirkL
[used] => 0
[buy_price] => 3.879
[buy_quantity] => 4
[sell_price] => 4.174
[sell_quantity] => 0
[total_buy] => 9
[total_sell] => 3
)
答案 0 :(得分：-1)
你通过创建所有那些额外的循环，变量，数组等来使事情变得如此复杂。没有经过测试，但这应该有效;
$inventory = json_decode($len,true);
$buys = $sells = array();
$cars = array();
foreach($inventory as $index => $item){
$car = $item['car_name'] . $item['edition_num'];
$buys[$car] += $item['buy_quantity'];
$sells[$car] += $item['sell_quantity'];
$numberofCars[$car]++;
$cars[$car][] = $item;
}
foreach($cars as $car_group){
foreach($car_group as $index => $car){
if($index == count($car_group)-1){
$car['total_buy'] = $buys[ $car['car_name'] . $car['edition_num'] ];
$car['total_sell'] = $sells[ $car['car_name'] . $car['edition_num'] ];
}
print_r($car);
}
}