DirectoryIterator; 2 levels deep

[Tarh]

Here's a list of the directories in the current folder (they are all directories, there are no files or links):

./temp
./temp/sub1
./temp/sub1/lowest1
./temp/sub1/lowest2
./temp/sub2
./temp/sub2/lowest3
./temp/sub2/lowest4

Here's the PHP script in the current folder:

<?php
    //Make the iterator for the temp directory
    $dir = new DirectoryIterator('temp');

    //Print the top level name
    echo $dir->getBasename(), '<br>';

    //Loop through all the subdirectories
    foreach ($dir as $subdir) {
        if (!$subdir->isDir() || $subdir->isDot()) continue;

        //Print the subdirectory name
        echo '> ', $subdir->getBaseName(), '<br>';

        //Loop through all the (sub)subdirectories
        foreach ($subdir as $subsubdir) {
            if (!$subsubdir->isDir() || $subsubdir->isDot()) continue;

            //Print the (sub)subdirectory name
            echo '>> ', $subsubdir->getBaseName(), '<br>';
        }
    }
?>

I would expect this output:

.
> sub1
>> lowest1
>> lowest2
> sub2
>> lowest3
>> lowest4

However, the code produces this:

.
> sub1
>> sub1
>> sub2

In fact, it doesn't matter how many loops I nest; it stays in the same directory.

Adding this line before the inner loop fixes the issue:

$subdir = new DirectoryIterator($subdir->getRealPath()); 

Where did I go wrong?

For my purposes, I need to recurse to a depth of exactly 2; hence I am not using RecursiveDirectoryIterator.

[crmalibu]

foreach isn't creating a new iterator for you. That's why you needed to explicitly do it.

foreach ($dir as $subdir) {
}
// equivalent to...
$dir->rewind();
while($dir->valid()) {
    //$subdir = $dir->current();
    $dir->next();
}





// and
var_dump($dir === $dir->current()); // always true

// and thats why both echos are identical
foreach ($dir as $subdir) {
    echo $dir->getBasename();
    echo $subdir->getBasename();
} 

[Tarh]

That makes sense. Thanks.

[Salathe]

Further to crmalibu's post, your inner foreach loop would need something like:

foreach (new DirectoryIterator($subdir->getPathname()) as $subsubdir) { 

Also, you could change the "info class" for the DirectoryIterator to return new DirectoryIterators (look for the SplFileInfo::setInfoClass documentation):

// ...
$dir->setInfoClass('DirectoryIterator');
foreach ($dir as $subdir) {
  // ...
  foreach ($subdir->getFileInfo() as $subsubdir) {
    // ...
  }
} 

Thirdly, you could also use a RecursiveDirectoryIterator and restrict the output to only two levels. For example:

$dir = new RecursiveDirectoryIterator('temp');
$it  = new RecursiveIteratorIterator($dir, RecursiveIteratorIterator::SELF_FIRST);

//Loop through all the subdirectories
foreach ($it as $file) {
    // Restrict to two levels only and ignore non-directory and dot files 
    if ($it->getDepth() >= 2 || ! $it->isDir() || $it->isDot())
        continue;
    
    // Print the directory name
    echo str_repeat('>', $it->getDepth() + 1), ' ', $it->getBasename(), "\n";
} 

If you're lucky enough to be allowed to play with PHP 5.3, you could also make good use of the FilesystemIterator.

[crmalibu]

lol

class CallbackFilterIterator extends FilterIterator {
    protected $callback;
    public function __construct(Iterator $it, $callback) {
        parent::__construct($it);
        $this->callback = $callback;
    }
    public function accept() {
        return call_user_func($this->callback, $this->getInnerIterator());
    }
}

$it = new CallbackFilterIterator(new RecursiveIteratorIterator(new RecursiveDirectoryIterator($path), RecursiveIteratorIterator::SELF_FIRST), function($it) {
    return !$it->isDot() && $it->getDepth() < 2;
});

foreach($it as $fileInfo){
    echo "{$fileInfo->getPathName()}\n";
} 

[AnthonySterling]

lol

class CallbackFilterIterator extends FilterIterator {
    protected $callback;
    public function __construct(Iterator $it, $callback) {
        parent::__construct($it);
        $this->callback = $callback;
    }
    public function accept() {
        return call_user_func($this->callback, $this->getInnerIterator());
    }
}

$it = new CallbackFilterIterator(new RecursiveIteratorIterator(new RecursiveDirectoryIterator($path), RecursiveIteratorIterator::SELF_FIRST), function($it) {
    return !$it->isDot() && $it->getDepth() < 2;
});

foreach($it as $fileInfo){
    echo "{$fileInfo->getPathName()}\n";
} 

Bravo, now that I DO like!

Although, I'm still unsure of the use of lambda functions. Just when I'm starting to get used to the syntax too!

[Tarh]

Wow! This could quickly spiral into another Write a FOR loop in PHP that prints the numbers 0-9 to the page.

Not that that's a bad thing; I'd love to bring back my genetic algorithm classes for this problem!

[crmalibu]

Not that that's a bad thing; I'd love to bring back my genetic algorithm classes for this problem!

That was the one I remembered most lol.

[Salathe]

I'd love to bring back my genetic algorithm classes for this problem!

Please do.

[crmalibu]

Ok, this is scary, because I had never seen this before I wrote that code. I was looking for a way to filter before all the recursion actually happened, and stumbled upon this

http://www.php.net/~helly/php/ext/sp...nc-source.html