Python 3.4语法错误以及如何修复

Question

虽然以下行在Python 3.6上被接受，但在Python 3.4上我收到了一个语法错误：

struct.pack_into('q' * len(GeoFence_lat_list)*2,buff,264,*GeoFence_lat_list, *GeoFence_lon_list)

其中GeoFence_lon\ulist是一个声明为：的数组

Geo_Fence_list = []
GeoFence_lat_list = []
GeoFence_lon_list = []

以下是更多要查看的代码：

if (Polygon_available_size == 0):
buff = ctypes.create_string_buffer(workzone_size)
struct.pack_into('q' * 33, buff, 0, Speed_limit, Speed_Zone_lat, Speed_Zone_longi, Speed_Zone_heading_radians,
Speed_Zone_ITIS_CODE, Speed_Zone_2_lat, Speed_Zone_2_longi, Speed_Zone_2_heading_radians, Speed_Zone_2_ITIS_CODE,G20_lat, G20_longi,
G20_heading_radians, G20_ITIS_CODE,W20_lat, W20_longi, W20_heading_radians ,W20_ITIS_CODE,W21_5BR_lat,W21_5BR_longi, W21_5BR_heading_radians,
W21_5BR_ITIS_CODE,W21_5AR_lat,W21_5AR_longi, W21_5AR_heading_radians, W21_5AR_ITIS_CODE,First_Taper_lat,First_Taper_longi,
Last_Taper_lat, Last_Taper_longi, 2020, 2456,60, Polygon_available_size)
elif (int(Polygon_available_size) > 0):
geo_fence_size = struct.calcsize('q' * len(GeoFence_lat_list)*2)
#print("geo_fence_size", geo_fence_size)
workzone_size = workzone_size + geo_fence_size
buff = ctypes.create_string_buffer(workzone_size)
struct.pack_into('q' * 33, buff, 0, Speed_limit, Speed_Zone_lat, Speed_Zone_longi, Speed_Zone_heading_radians,
Speed_Zone_ITIS_CODE, Speed_Zone_2_lat, Speed_Zone_2_longi, Speed_Zone_2_heading_radians, Speed_Zone_2_ITIS_CODE,G20_lat, G20_longi,
G20_heading_radians, G20_ITIS_CODE,W20_lat, W20_longi, W20_heading_radians ,W20_ITIS_CODE,W21_5BR_lat,W21_5BR_longi, W21_5BR_heading_radians,
W21_5BR_ITIS_CODE,W21_5AR_lat,W21_5AR_longi, W21_5AR_heading_radians, W21_5AR_ITIS_CODE,First_Taper_lat,First_Taper_longi,
Last_Taper_lat, Last_Taper_longi, 2020, 2456,60, Polygon_available_size)
struct.pack_into('q', * len(GeoFence_lat_list)*2,buff,264,*GeoFence_lat_list, *GeoFence_lon_list)
GeoFence_lat_list.clear()
GeoFence_lon_list.clear()
packed_flag = 1

Answer 1

Python 3.4每次调用只允许一个未封装的参数。

您的原始代码使用多个解包，只是将多个列表附加到字节缓冲区中。只需多次调用struct.pack_into()，每个部分都有适当的偏移量，就可以实现同样的效果。

start = 264
struct.pack_into(str(len(GeoFence_lat_list)) + 'q', buff, start, *GeoFence_lat_list);
start += 8 * len(GeoFence_lat_list)
struct.pack_into(str(len(GeoFence_lon_list)) + 'q', buff, start, *GeoFence_lon_list);