how to iterate through all folders inside subfolders of root level folders

Question

below is the code to iterate through root level folders which downloads folder starts with "a" and download sub folders from it starting with any letter. I want to download all the folder levels and not just the subfolder.how do I achieve this

foreach($folder in $RootFolder.SubFolders)
{
if($folder.Name.StartsWith("a")
{
ProcessFolder($folder.Url)
}
foreach($folder in $folders.SubFolders)
{
ProcessFolder($folder.Url)

}

}

Answer 1

I would do something like this:

function ProcessAllSubfolders($folderCollection)
{
    foreach ($folder in $folderCollection)
    {
        if ($folder.Subfolders.Count -gt 0)
        {
            ProcessAllSubfolders($folder.SubFolders)
        }

        ProcessFolder($folder.Url)
    }
}

# main

foreach ($folder in $RootFolder.SubFolders)
{
    if ($folder.Name.StartsWith("a"))
    {
        if ($folder.Subfolders.Count -gt 0)
        {
            ProcessAllSubfolders($folder.SubFolders)
        }

        ProcessFolder($folder.Url)
    }
}

(I realize there's some code duplication there and probably there's a more elegant way of doing it, but what do you want for a 3 minute answer?)