::解决方案::

使用@RomanPerekhrest 的答案稍作修改，我得到了我需要的东西。这会添加多个目录以递归搜索，同时过滤掉某些文件夹(在我的例子中:“_thumbs”文件夹)。最终代码如下:

$dir1 = new RecursiveDirectoryIterator("./folder01");
$dir2 = new RecursiveDirectoryIterator("./folder02");
$dir3 = new RecursiveDirectoryIterator("./folder03");
$iterators = new AppendIterator();

$filter = function ($file, $key, $iterator) {
    if ($iterator->hasChildren() && $file->getFilename() != "_thumbs") {
        return true;
    }
return $file->isFile();
};

$iterators->append(new RecursiveIteratorIterator( $dir1 ));
$iterators->append( $dir2 );
$iterators->append(new RecursiveIteratorIterator(new RecursiveCallbackFilterIterator($dir3, $filter)));

$rgIt = new RegexIterator($iterators, "/^.+\.jpg$/i");
$files = iterator_to_array($rgIt);

::原始问题::

我很难弄清楚 RegexIterator。我正在尝试过滤掉 RecursiveIteratorIterator 扫描过的父目录中的目录。在我下面的代码中，$dir3 有多个目录，因此有 RecursiveIteratorIterator，但是它也有一个“_thumbs”目录，我不希望它处理。 RegexIterator 当前正在过滤并保留 .jpg 图像，但我还想杀死从“_thumbs”目录中抓取的所有内容。

$dir1 = new RecursiveDirectoryIterator("./folder01");
$dir2 = new RecursiveDirectoryIterator("./folder02");
$dir3 = new RecursiveDirectoryIterator("./folder03"); // <<< this dir has a _thumbs directory that I don't want to process
$iterators = new AppendIterator();

$iterators->append(new RecursiveIteratorIterator( $dir1 ));
$iterators->append( $dir2 );
$iterators->append(new RecursiveIteratorIterator( $dir3 ));

$rgIt = new RegexIterator($iterators, "/^.+\.jpg$/i");  //<<< this filters and keeps .jpg images.  I don't fully understand the syntax though
$files = iterator_to_array($rgIt);


usort($files, function($a, $b){
    if(filectime($a) == filectime($b)){
        return 0;
    }
    return filectime($a) > filectime($b) ? -1 : 1;
});

$files = array_slice($files, 0 , 18);

::EDIT01::

这是我尝试过的另一个测试，但也没有取得任何进展。尝试使用 RecursiveFilterIterator，但我怀疑我是否正确使用它。我得到的错误是“Argument 1 passed to RecursiveFilterIterator::__construct() must implement interface RecursiveIterator, instance of AppendIterator given”。

$dir1 = new RecursiveDirectoryIterator("./folder01");
$dir2 = new RecursiveDirectoryIterator("./folder02");
$dir3 = new RecursiveDirectoryIterator("./folder03");
$iterators = new AppendIterator();

$iterators->append(new RecursiveIteratorIterator( $dir1 ));
$iterators->append( $dir2 );
$iterators->append(new RecursiveIteratorIterator( $dir3 ));

class DirFilter extends RecursiveFilterIterator{
    public function accept(){
        $excludes = "/_thumbs";
        return !(in_array($this->getFilename(), $excludes));
    }
}

$filterItr = new DirFilter($iterators);

$rgIt = new RegexIterator($filterItr, "/^.+\.jpg$/i");
$files = iterator_to_array($rgIt);

最佳答案

在正则表达式模式中使用否定断言:

...
$rgIt = new RegexIterator($iterators, "/(?!\/_thumbs\/)^.+\.jpg$/i"); 
$files = iterator_to_array($rgIt);
...

如果以上方法对您不起作用，请尝试使用 RecursiveCallbackFilterIterator 过滤掉“拇指”图像:

$filter = function ($file, $key, $iterator) {
    if ($iterator->hasChildren() && $file->getFilename() == "_thumbs") {
        return true;
    }
    return $file->isFile();
};
...
$iterators->append( $dir2 );
$iterators->append(new RecursiveIteratorIterator(new RecursiveCallbackFilterIterator($dir3, $filter)));
...

关于php - RegexIterator 过滤图像，忽略特定目录，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/34543397/