关于python数列的交集

关于python数列的交集/usr/bin/pythonimport osimport jsonimport timedata = {}tcp_list = []port_list = []ports_list = []a = []b = []command = 'netstat -ano -p tcp| find "LISTENING" 'lines = os.popen(command).readlines()for line in lines:port = line.split()[1].split(':')[1]port_list.append(port)a = set(port_list)time.sleep(0.1)command = 'netstat -ano -p tcp| find "LISTENING" 'lines = os.popen(command).readlines()for line in lines:port = line.split()[1].split(':')[1]ports_list.append(port)b = set(ports_list)print set(a & b)for port in list(set(a & b)):port_dict = {}port_dict['{#TCP_PORT}'] = porttcp_list.append(port_dict)data['data'] = tcp_listjsonStr = json.dumps(data,sort_keys=True,indent=4)print jsonStr照理说port_list和ports_list获取的数据都是一样的,用set获取连个数列的交集应该没输出才对的.不用了,用错参数.