使用突破性开关

Question

在研究使用switch声明的更好方法时，我找到了这个stackoverflow示例。我希望做同样的事情，但与一捻：

switch($status) 
{ 
case "a": 
case "b": 
    echo "start execute code for case a and b"; 
case "a": 
    echo "continue to execute code for case a only"; 
case "b": 
    echo "continue to execute code for case b only"; 
case "a": 
case "b": 
    echo "complete code execution for case a and b"; 
break; 
case "c": 
    echo "execute code for case c"; 
break; 
case "d": 
    echo "execute code for case d"; 
break; 
case "e": 
    echo "execute code for case e"; 
break; 
case "f": 
    echo "execute code for case f"; 
break; 
default: 
    echo "execute code for default case"; 
} 

是，上述显然不按计划进行，因为字母“a”将下降，穿过直到碰到一个break锻炼。我只想知道是否有一种方法可以在不重复太多代码的情况下优雅地完成此任务。

Answer 1

一旦case匹配，PHP将忽略任何进一步case语句和直到该开关被闭合（}）或遇到break执行所有代码。 break也将终止交换机，所以你想要的是不可能的。

Answer 2

这是不正确的switch语句的用法。

您应该用一系列if语句替换您的交换机。

if($status == a || $status == b) { 
    echo "start execute code for case a and b"; 
    if(status == a) { 
     echo "continue to execute code for case a only"; 
    } 
    else { 
     echo "continue to execute code for case b only"; 
    } 
    echo "complete code execution for case a and b"; 
} 
else if ($status == c) { 
    echo "execute code for case c"; 
} 
... 
... 
else { 
    echo "execute code for default case"; 
} 

Answer 3

正如Marc B所说的那样（至少是用开关）不能做到。幸运的是，删除重复代码的一个好方法是定义方法，这样可以在需要时调用a和b共同的代码。

Answer 4

有一个在会$status没怎么可以=a和b，除非它是一个array我硝酸钾你想做的事，这是我证明概念

function runSwitch($status) { 

    if (in_array ("a", $status) && in_array ("b", $status)) { 
     echo "start execute code for case a and b" . PHP_EOL; 
    } 

    if (in_array ("a", $status)) { 
     echo "continue to execute code for case a only" . PHP_EOL; 
    } 

    if (in_array ("b", $status)) { 
     echo "continue to execute code for case b only" . PHP_EOL; 
    } 

    if (in_array ("c", $status)) { 
     echo "execute code for case c" . PHP_EOL; 
    } 

    if (in_array ("d", $status)) { 
     echo "execute code for case d" . PHP_EOL; 
    } 

    if (in_array ("e", $status)) { 
     echo "execute code for case e" . PHP_EOL; 
    } 

    if (in_array ("f", $status)) { 
     echo "execute code for case f" . PHP_EOL; 
    } 

    if (in_array ("c", $status) && in_array ("f", $status)) { 
     echo "continue to execute code for case c AND f only" . PHP_EOL; 
    } 

} 

例1

的

$status = array (
     "a" 
); 

runSwitch($status); 

输出

continue to execute code for case a only 

例2

$status = array (
     "a" , "b" 
); 


runSwitch($status); 

输出

start execute code for case a and b 
continue to execute code for case a only 
continue to execute code for case b only 

我希望这有助于

感谢

Answer 5

以下是我认为将是一个完美的解决方案：

switch($status) 
{ 
case "a": 
case "b": 
    echo "start execute code for case a and b"; 
    if($status == "a") echo "continue to execute code for case a only"; 
    if($status == "b") echo "continue to execute code for case b only"; 
    echo "complete code execution for case a and b"; 
break; 
case "c": 
    echo "execute code for case c"; 
break; 
case "d": 
    echo "execute code for case d"; 
break; 
case "e": 
    echo "execute code for case e"; 
break; 
case "f": 
    echo "execute code for case f"; 
break; 
default: 
    echo "execute code for default case"; 
} 

我不想在这里发明任何新东西。试图从这里的每个人的经验中学习。感谢所有向我提供答案的人。