Load a NumPy array from disk, either from a .npy file or from a .7z file. No need to include extension

load_ndarray.py

def load_ndarray(filename):
    """Load a NumPy array from disk into memory, with extension .npy or .7z. If no extension is
    included in the argument, first assume it's .npy, then .7z.

    Args:
        filename (str): Name of the NumPy array (in disk).

    Returns:
        ndarray
    """
    if filename.endswith('.npy'):
        compress = False
        status = 'uncompressed'  # Everything OK!
    elif filename.endswith('.7z'):
        compress = True
        status = 'compressed'
    else:
        file_npy = filename + '.npy'
        if file_npy in os.listdir():
            filename = file_npy
            compress = False
            status = 'uncompressed'
        else:
            file_7z = filename + '.7z'
            if file_7z in os.listdir():
                filename = file_7z
                compress = True
                status = 'compressed'
            else:
                raise FileNotFoundError

    # ---------------------------------
    size = os.stat(filename).st_size
    print('Loading {0:,} [{1}] bytes from disk... File: {2}'
          .format(size, status, filename))

    if compress:
        if shutil.which('7z') is None:
            raise FileNotFoundError('7z not found on the PATH!')
        subprocess.Popen('7z e ' + filename + ' -mmt', shell=True).wait()
        ndarray = np.load(filename[:-3] + '.npy')
    else:
        ndarray = np.load(filename)
        print('Succesfully loaded {0!s}-array ({1:,} bytes) from {2}!'
              .format(ndarray.shape, size, filename))

    return ndarray