def get_scan_list(scandescriptor_list):
    """
    determine which is the scan list for each radar

    Parameters
    ----------
    scandescriptor : list of string
        the list of all scans for all radars

    Returns
    -------
    scan_list : list of lists
        the list of scans corresponding to each radar

    """
    descrfields = scandescriptor_list[0].split(':')
    if len(descrfields) == 1:
        # one radar
        return [scandescriptor_list]

    # one or more radars
    # check how many radars are there
    radar_list = set()
    for scandescriptor in scandescriptor_list:
        radar_list.add(scandescriptor.split(':')[0])
    nradar = len(radar_list)

    # create the list of lists
    scan_list = [[] for i in range(nradar)]
    for scandescriptor in scandescriptor_list:
        descrfields = scandescriptor.split(':')
        ind_rad = int(descrfields[0][5:8])-1
        scan_list[ind_rad].append(descrfields[1])

    return scan_list