PHP 在 switch case 中转换 ENUM 不起作用

Question

        echo $state;  //debug
        switch($state){
            case "Sleeping":
                $label = "Is Sleeping";
            case "Running":
                $label = "Is Running";
            default: 
                $label = "Could not retrieve state";
        }

$state 由 SQL 数据库（枚举类型）填充，回显消息打印“Sleeping”，但 $label 填充的是默认值

Answer 1

PHP switch 语句在找到匹配项后继续执行 switch 块的其余部分，直到找到 break; 语句。您需要在每个案例的末尾添加 break;：

        echo $state;  //debug
        switch($state){
            case "Sleeping":
                $label = "Is Sleeping";
                break;
            case "Running":
                $label = "Is Running";
                break;
            default: 
                $label = "Could not retrieve state";
        }

Answer 2

在您的情况下，选择 match (PHP 8) 表达式明显更短，并且不需要 break 语句。

$state = "Running";
$label = match ($state) {
    "Sleeping"=> "Is Sleeping",
    "Running" => "Is Running",
    default => "Could not retrieve state"
};
echo $label; // "Is Running"

Answer 3

完整性：

$states = [
    'Sleeping' => 'Is Sleeping',
    'Running' => 'Is Running',
];
echo $states[$state] ?? 'Could not retrieve state';

PHP 在 switch case 中转换 ENUM 不起作用

PHP Translating a ENUM in switch case not working

php

enums

switch-statement