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循环通过数组求一个元素的和

arrays php

JimB814 · 技术社区 · 7 年前

$cart = [

    1031 => [
        'id'    => '1031',
        'model' => 'tr16',
        'price' => 100,
        'discount_applied' => '',
        'promo_name' => '',
        'promo_id' => ''
    ],
    1032 => [
        'id'    => '1032',
        'model' => 'tr16g',
        'price' => 100,
        'discount_applied' => '',
        'promo_name' => '',
        'promo_id' => ''
    ],
    1034 => [
        'id'    => '1034',
        'model' => 'tr17g',
        'price' => 100,
        'discount_applied' => '',
        'promo_name' => '',
        'promo_id' => ''
    ]
];

我有一个ID数组,表示符合折扣条件的项目,如下所示:

$itemIds = [

    0 => [
        0 => 1031
    ],
    1 => [
        0 => 1032
    ]
];

我循环遍历每个数组并更改ID所在的价格 $cart 匹配中的ID $itemIds

foreach($cart as &$item) {
    foreach($itemIds as $ids) {
        foreach($ids as $key => $value) { 

            if ($item['id'] == $value)   
            {             
                $item['discount_applied'] = $item['price'] * 0.2;
                $item['price'] = $item['price'] * .80;
                $item['promo_name'] = 'Test promo';
                $item['promo_id'] = 36;
            }     
        }
    }
}

在循环之前和之后将购物车打印到屏幕上显示它按预期工作。

但是,我在尝试循环修改后的 $购物车 计算每个折扣的总和。

$cart['total_discount'] = 0;
foreach($cart as $item) 
{
    $cart['total_discount'] += $item['discount_applied'];
}
echo 'Total discount:' . $cart['total_discount'];

我希望看到折扣的总和=40,但实际上是=60。在循环前后将购物车打印到屏幕上显示1031和1032项的值为20 discount_applied

任何帮助我确定哪里有一个或多个错误是感激的。

如果你想复制/粘贴,这里有所有的代码。

$cart = [

    1031 => [
        'id'    => '1031',
        'model' => 'tr16',
        'price' => 100,
        'discount_applied' => '',
        'promo_name' => '',
        'promo_id' => ''
    ],
    1032 => [
        'id'    => '1032',
        'model' => 'tr16g',
        'price' => 100,
        'discount_applied' => '',
        'promo_name' => '',
        'promo_id' => ''
    ],
    1034 => [
        'id'    => '1034',
        'model' => 'tr17g',
        'price' => 100,
        'discount_applied' => '',
        'promo_name' => '',
        'promo_id' => ''
    ]
];

$itemIds = [

    0 => [
        0 => 1031
    ],
    1 => [
        0 => 1032
    ]
];  

echo '<h2>Cart BEFORE discount</h2>'; echo '<pre>';print_r($cart); echo '</pre>';


foreach($cart as &$item) {
    foreach($itemIds as $ids) {
        foreach($ids as $key => $value) { 

            if ($item['id'] == $value)   
            {             
                $item['discount_applied'] = $item['price'] * 0.2);
                $item['price'] = $item['price'] * .80;
                $item['promo_name'] = 'Test promo';
                $item['promo_id'] = 36;
            }     
        }
    }
}

echo '<h2>Cart AFTER discount</h2>'; echo '<pre>';print_r($cart); echo '</pre>';

$cart['total_discount'] = 0;
foreach($cart as $item) 
{
    echo $item['discount_applied'] . '<br>';
    $cart['total_discount'] += $item['discount_applied'];
}
echo 'Total discount:' . $cart['total_discount'];

1 回复 | 直到 7 年前

Dave 7 年前

你使用 &$item 在初始循环中也需要在最终循环中使用。将折扣总额相加的循环。您还需要查看折扣值是否为数字,因为在您发布的代码中,购物车中的第三个项目的折扣值为空,这将在尝试将其添加到折扣总额时引发非数字错误。

$cart['total_discount'] = 0;
foreach($cart as &$item) {
    echo '*' . $item['discount_applied'] . '*<br />';  // just to show what is or isn't there
    $cart['total_discount'] += (is_numeric($item['discount_applied']) ? $item['discount_applied'] : 0);
}
echo 'Total discount:' . $cart['total_discount'];