我创建了一个包含以下行和值的mysql表:
category | item_name
=======================
Dinner | Lobster
Dinner | Pizza
Lunch | Sandwich
Lunch | Soup
Lunch | Salad
-------------------------
然后我查询数据库,结果放在数组"$menu_selected"中。我循环遍历"$menu_selected"以显示结果。
foreach($menu_selected as $m):
echo $category = $m->category . "<br>";
echo $item_name = $m->item_name . "<br><br>";
endforeach;
输出:
Dinner
Lobster
Dinner
Pizza
Lunch
Sandwich
Lunch
Soup
Lunch
Salad
如何在 PHP 中过滤类别,使其不会仅回显每个类别的第一个实例?类别行值并不总是"晚餐"或"午餐",我希望能够回显类别而不将其与 if($category =='Dinner'){} 这样的常量进行比较。我花了一周时间研究,但无法弄清楚。任何人的帮助将不胜感激。
我希望输出看起来像这样:
**Dinner**
Lobster
Pizza
Sandwich
**Lunch**
Sandwich
Soup
Salad
确保在查询中按类别排序。 然后只需在循环外添加一个$category变量,如果该变量已更改,则输出标头。
$category = '';
foreach($menu_selected as $m) {
if ($m->category != $category) {
echo "**$m->category** <br>";
$category = $m->category;
}
echo $m->category . "<br>";
echo $m->item_name . "<br><br>";
}
$cat_item_array = ARRAY();
foreach($menu_selected as $m) {
if (!isset($cat_item_array[$m->category])) {
$cat_item_array[$m->category] = $m->item_name;
echo "found new category: ".$m->category . " (Added item: ".$m->item_name.")<br>";
continue;
}
$cat_item_array[$m->category] = $m->item_name;
echo "Added item ".$m->item_name." to category ".$m->category.".<br><br>";
}
print '<pre>'; var_dump($cat_item_array); print '</pre>';
只需使用 2 foreach 方法。第一个用于类别 第二个用于项目
foreach($menu_selected as $m1):
echo $category = $m1->category . "<br>";
foreach($menu_selected as $m):
echo $item_name = $m->item_name . "<br><br>";
if ($m->category != $m1->category)
{
break;
}
endforeach;
endforeach;