rebin_folders_slow.py

def rebin_folders(paths, max_files_per_folder=16000):
    parent_paths = Counter(Path(p).parent for p in paths)
    rebin_parents = set(k for k,v in parent_paths.items() if v > max_files_per_folder)

    rebinned = set(p for p in paths if Path(p).parent in rebin_parents)
    untouched = set(paths) - rebinned

    rebinned_tuples = []
    chunked = list(chunks(list(rebinned), max_files_per_folder))
    min_len = len(str(len(chunked) + 1))  # start at 1
    for i, chunked_paths in enumerate(chunked, start=1):
        rebinned_tuples.extend([(p, str(Path(p).parent / str(i).zfill(min_len) / Path(p).name)) for p in chunked_paths])

    return untouched, rebinned_tuples