PHP increment variable with glob

New to PHP...searched the manual, just don't understand how to put it all together. I'm trying to go through a folder and display each html file as it's contents...that part works. I can't figure out how to change a div id incrementally.

This code works for displaying the what I want I just need unique id's in my divs.

$dir = realpath('./path/to/folder/of_files/');
foreach (glob($dir .'/*.html') as $page){
   $div = file_get_contents($page);  
   echo ("<div class=\"interface\开发者_如何转开发" id=\"ID_$id\">$div</div>");
}

Thanks in advance.

---

If $id is just some integer you can stick an $id++; somewhere...

$id = 1;
$dir = realpath('./path/to/folder/of_files/');

foreach (glob($dir .'/*.html') as $page){
   $div = file_get_contents($page);  
   echo ("<div class=\"interface\" id=\"ID_$id\">$div</div>");
   $id++;
}

---

Do it like this:

$dir = realpath('./path/to/folder/of_files/');
$id = 1;
foreach (glob($dir .'/*.html') as $page)
{
   $div = file_get_contents($page);  
   echo ("<div class=\"interface\" id=\"ID_{$id}\">$div</div>");
   $id++; //this is just... $id = $id + 1;
}

---

Or, you can auto increment using foreach's AS syntax.

$dir = realpath('./path/to/folder/of_files/');
foreach (glob($dir .'/*.html') as $id => $page)
{
   $div = file_get_contents($page);  
   echo ("<div class=\"interface\" id=\"ID_{$id}\">$div</div>");
}

Note that you may want to increment $id in the 'echo' statement if you don't want $id to start at 0.