如何从产品列表中

Question

我有一个清单产品（包括类别和数量）

$html = "";
foreach ($products as $product) {
   $html .= $product->category;
   $html .= $product->name;
   $html .= $product->quantity;
}
echo $html;

按照此列表

Category | Product | Quantity
Timsum       T1         10
Timsum       T2         20
Timsum       T3         30  
Sauces       S1         5  
Sauces       S2         15

如何汇总组并显示每个类别的最后一行

Category | Product | Quantity
Timsum       T1         10
Timsum       T2         20
Timsum       T3         30 
**Sum Timsum            60**    
Sauces       S1         5  
Sauces       S2         15
**Sum Sauces            20** 

Answer 1

按类别名称排序结果集，然后使用临时变量：

$qty = 0;
$last_cat = null;

foreach ($products as $product) {
  if ($product->category != $last_cat && $last_cat) {
    echo "**Sum $last_cat $qty\n";
    $qty = 0;
    $last_cat = $product->category;
  }

  printf("%s\t%s\t%s\n",
    $product->category, $product->name, $product->quantity);

  $last_cat = $product->category;
  $qty += $product->quantity;
}

Answer 2

添加$sum变量来记录累积的数量，并在类别移动时制作一些条件来跟踪该作业：

$html = "";
$first_iteration = FALSE;
$sum = 0;

foreach ($products as $product) {

   if (!$first_iteration)
   {
      $first_iteration = TRUE;
      $temp_category = $product->category;
   }

   if ($temp_category != $product->category)
   {
      html .= "**".$temp_category;
      html .= $sum;
      $sum = 0;
      $temp_category = $product->category;
   }

   $html .= $product->category;
   $html .= $product->name;
   $html .= $product->quantity;

   $sum += (integer) $product->quantity;
}
html .= "**".$temp_category;
html .= $sum;

echo $html;