在PHP中，我可以在switch语句中获得case语句的总数吗？

Question

Is there a way to return the total number of (case) instances there are in a switch statement? Something like this:

$id = $_GET['id'];

switch ($id) {
  case "item1" :
  $data = 'something1';
  break;

  case "item2" :
  $data = 'something2';
  break;
}

echo $data;

But the reasoning for it is there are multiple files with these switch statements in them, but the number of them vary depending on the file. I'd ideally like to be able to loop through these switch statements by incrementing the "id". Any ideas on if this is possible?

Answer 1

If you're just assigning values based on another value you could use an array instead:

$idToData = array(
    'item1' => 'something1',
    'item2' => 'something2',
);
$data = 'default';
if (isset($_GET['id']) && array_key_exists($_GET['id'], $idToData)) {
    $data = $idToData[$_GET['id']];
}
echo $data;

The advantage of an array is that it can be extended and the number of items can be counted with count()

Answer 2

Not without altering the value of $id and removing break statements.. but that kind of defeats the purpose. Is there a reason you need to know how many?

I would just grep the files you want to find out about

find -name '*php' | xargs grep 'case'

Answer 3

Ah - I think I see what you're after. What you could do is add a default: case that terminates the loop, rather than trying to count. Eg

for($id = 1; !$quit; $id++)
{
    switch("item" . $id) {
    case "item1":
         // Do something
         break;
    case "item<n>":
         // Do something else
         break;
    default:
         $quit = true;
    }
}

Question is: why not just do all this without a loop and case statements by just ... putting one statement after another?

Answer 4

您可以使用token_get_all（）执行您所要求的操作 ，但很可能这不是您实际问题的最佳解决方案。

Answer 5

Actually you can do this reliably using token_get_all() . Here is an example of using that function to find all the define() usages in a PHP file . You will need to build a finite state machine (similar to the linked one) to look for switch statements and then the subordinate case statements. You may or may not want to make sure you deal with nested switch statements correctly.

Answer 6

OK, let's say the URL looks like this:

somesite.com/ajax/getinfo.php?id=news

Then you can take $_GET[id] value and process it with a switch.

If I imagined your code correcly:

$section=$_GET[id];
switch($section) {
case "1":
break;
.
.
.
default:

}

If that is not correct, so pardon my English. Please explain it a bit more, it stills a bit ambiguous.

Answer 7

Actually, this code will work:

$i = 0;
switch(something)
{
    case "item".$i++: //something
        break;
    case "item".$i++: //something
        break;
    default: //something
        break;
}