如果该字段为空以返回n/a，我如何让switch命令工作

Question

您好，我写了以下代码，但我有一个小问题。

在我的数据库中，有一个名为gf_gemstone的字段，我写了一个切换脚本(如下所示)

如果返回N/A的字段为empty，我要写的最后一部分。但是无论我做什么，我都不能让它工作。有人能帮上忙吗。

 case "gf_gemstone_Amazon1a":
            switch ($value) {
                case "Agate":
                    return "agate";
                    break;
                case "Amethyst":
                    return "amethyst";
                    break;
                case "Aquamarine":
                    return "aquamarine";
                    break;
                case "Black Diamond":
                    return "black-diamond";
                    break;
                case "Black Sapphire":
                    return "sapphire";
                    break;
                case "Blue Diamond":
                    return "blue-diamond";
                    break;
                case "Blue Sapphire":
                    return "blue-sapphire";
                    break;
                case "Blue Topaz":
                    return "blue-topaz";
                    break;
                case "Chalcedony":
                    return "chalcedony";
                    break;
                case "Citrine":
                    return "citrine";
                    break;
                case "Cognac Diamond":
                    return "brown-diamond";
                    break;
                case "Diamond":
                    return "diamond";
                    break;
                case "Emerald":
                    return "emerald";
                    break;
                case "Garnet":
                    return "garnet";
                    break;
                case "Green Amethyst":
                    return "green-quartz";
                    break;
                case "Green Quartz":
                    return "green-quartz";
                    break;
                case "Green Sapphire":
                    return "green-sapphire ";
                    break;
                case "Lemon Quartz":
                    return "lemon-quartz";
                    break;
                case "Morganite":
                    return "morganite";
                    break;
                case "Multi Sapphire":
                    return "sapphire";
                    break;
                case "Onyx":
                    return "onyx";
                    break;
                case "Opal":
                    return "opal";
                    break;
                case "Orange Sapphire":
                    return "sapphire";
                    break;
                case "Peridot":
                    return "peridot";
                    break;
                case "Pink Sapphire":
                    return "pink-sapphire";
                    break;
                case "Pink Sapphire":
                    return "pink-sapphire";
                    break;
                case "Pink Topaz":
                    return  "pink-topaz";
                    break;
                case "Pink Tourmaline":
                    return "pink-tourmaline";
                    break;
                case "Quartz":
                    return "quartz";
                    break;
                case "Rose Quartz":
                    return "rose-quartz";
                    break;
                case "Rhodolite Garnet":
                    return "rhodolite-garnet";
                    break;
                case "Ruby":
                    return "ruby";
                    break;
                case "Sapphire":
                    return "sapphire";
                    break;
                case "Smokey Quartz":
                    return "smoky-quartz";
                    break;
                case "Spessartite":
                    return "spessartite-garnet";
                    break;
                case "Tanzanite":
                    return "tanzanite";
                    break;
                case "Tsavorite":
                    return "tsavorite";
                    break;
                case "Turquoise":
                    return "turquoise";
                    break;
                case "White Sapphire":
                    return "sapphire";
                    break;
                case "Yellow Diamond":
                    return "yellow-diamond";
                    break;
                case "Yellow Sapphire":
                    return "sapphire";
                    break;
                        case "":
                    return "N/A";
                    break;
              default: return "";
            }
            break;

Answer 1

你可以把它写得更简洁：

$stones = array('Agate' => 'agate', 'Amethyst' => 'amethyst', etc...);
if (in_array($value, array_keys($stones))) {
   return $stones[$val];
} else {
   return "N/A";
}

Answer 2

@MarcB的答案更精确，但是，如果你想使用switch ... case，对NULL值使用如下：

case (NULL === $value):
    return "N/A";