在 Foreach 循环中使用条件过滤值并进行回退答案

【问题标题】：Conditional Inside A Foreach Loop To Filter Value And Have A Fall Back在 Foreach 循环中使用条件过滤值并进行回退
【发布时间】：2018-07-18 09:03:53
【问题描述】：

我有一个奇怪的问题，我无法解决它。我尝试了很多不同的方法来获得预期的结果，但没有成功。我正在寻找的是一组规则，例如如果在循环中满足条件，则回退。所以这就是我迄今为止所做的，但尝试了多种不同的方式。即使定义了国家/地区、邮政编码和运输方式，我总是得到作为匹配项的后备。几乎就像它忽略了这些值。

如果有人能指出正确的方向，我将不胜感激。

$country        = 'GB';
$postCode       = "LE5";
$shippingMethod = "subscription_shipping";

$shippingMatrix = array(
    array(
        "country"            => "GB",
        "isPostCodeExcluded" => "LE5",
        "shippingMethod"     => "subscription_shipping",
        "carrier"            => "Royal Mail",
        "carrierService"     => "Royal Mail",
    ),
    array(
        "country"            => "GB",
        "isPostCodeExcluded" => false,
        "shippingMethod"     => "subscription_shipping",
        "carrier"            => "DHL",
        "carrierService"     => "DHL",
    ),
    array(
        "country"            => false,
        "isPostCodeExcluded" => false,
        "shippingMethod"     => "subscription_shipping",
        "carrier"            => "Fallback",
        "carrierService"     => "Fallback",
    ),
    array(
        "country"            => "GB",
        "isPostCodeExcluded" => false,
        "shippingMethod"     => "standard_delivery",
        "carrier"            => "DPD",
        "carrierService"     => "DPD",
    ),
);

$carriers = [];
foreach ($shippingMatrix as $matrix) {
    // If only Shipping Method is matched then fall back will be the result
    if ($shippingMethod === $matrix['shippingMethod']) {
        $carriers = [
            $matrix['carrier'],
            $matrix['carrierService'],
        ];
        // If only Shipping Method & Country is matched then fall back will be the result DHL
        if ($country === $matrix['country']) {
            $carriers = [
                $matrix['carrier'],
                $matrix['carrierService'],
            ];
            // If only Shipping Method & Country & PostCode is matched then fall back will be the result Royal Mail
            if ($postCode === $matrix['isPostCodeExcluded']) {
                $carriers = [
                    $matrix['carrier'],
                    $matrix['carrierService'],
                ];
            }
        }
    }
}

var_dump($carriers);

【问题讨论】：

标签： if-statement multidimensional-array foreach filtering conditional-statements

【解决方案1】：

感谢您的回复，但这不是必需的。经过一个很好的旧想法之后，我犯了将我的类型混合在一起的新手错误。

$carriers = [];
foreach ($shippingMatrix as $matrix) {
    if ($shippingMethod === $matrix['shippingMethod'] && $country === $matrix['country']) {
        if ($postCode === $matrix['isPostCodeExcluded']) {
            $carriers = [
                $matrix['carrier'],
                $matrix['carrierService'],
            ];
        }
    }

    if ($shippingMethod === $matrix['shippingMethod'] && $country !== $matrix['country'] && !$country) {
        $carriers = [
            $matrix['carrier'],
            $matrix['carrierService'],
        ];
    }
}

【讨论】：

【解决方案2】：

$carriers 变量未用作数组表示法，因此值被覆盖。您只需将 $carriers 转换为 $carriers[] 即可。

下面是示例。

$carriers[]  = [
            $matrix['carrier'],
            $matrix['carrierService'],
          ];

【讨论】：