如何return不同类型的数组？

Question

我在 C# 中遇到的高级问题是制作描述机器人控制网络数据包 (Ethercat) 的数据结构的单个副本，然后使用该单个数据结构从集合中提取数据数据包。

当尝试使用累积数据包中的数据时会出现问题，因为数据结构与指定类型的强制转换或调用函数存在隐式重复。为了帮助解释目标，我编写了一个 python 程序来执行我想要的操作，并希望帮助确定是否可以在 C# 中执行此操作。

我在 C# 中面临的挑战是单个函数 "get_vector"，其中 returns 是可变数值类型的同类集合。这种类型定义在包结构中，在python中可以不用定义重新定义数据结构就可以使用。

import struct

# description of the complete packet
class PACKET_STRUCTURE :

# given a field name and a list of packets, return a vector
# this is the function that seems impossible in C# because the type of what is returned changes
def get_vector(self, name, packet_list):
    # locate the packet definition by the name of the vector
    result = [x for x in self.packet_def if x.field_name == name]

    # without error checking, pos contains the location of the definition
    pos = result[0].position;

    # decode ALL the pacckets in the (encoded) packet list - returning a list of [time_sec, status, position
    # in C# this step is similar to  using Marshal.PtrToStructure to transform from byte[] to a struct
    decoded_packet_list = [struct.unpack(self.fmt_str, packet) for packet in packet_list];

    # from the list of decoded_packets, extract the desired field into its own list          
    vector = [decode[pos] for decode in decoded_packet_list]

    # in C# this is similar to:
    # var CS_vector = decode_packet_list.Select(item => item.field_name).ToArray();
    # so far in C# there is no duplication of the packet structure.
    # but after this point, assume I cast CS_vector to object and return it - 
    # to use the object, I've not figured out how to avoid casting it to some type of array
    # eg double[], int32[]                        
    return vector        

    def __init__(self):
        self.packet_def = list();
        self.fmt_str = "<";
        self.cnt = 0;

    # add description of single item to the structure
    def add(self, struct_def) :
        struct_def.position = len(self.packet_def);
        self.packet_def.append(struct_def);
        self.fmt_str += struct_def.type;                

    # create a simple packet based on a counter based on the defined structure
    def make_packet(self):
        vals = [self.cnt*10+x for x in range(0, len(self.packet_def))];
        self.cnt += 1;
        pk = apply(struct.pack, [self.fmt_str] + vals)
        # print len(pk), ["%c" % x for x in pk]
        return pk

    def get_names(self):
        return [packet_items.field_name for packet_items in self.packet_def];


# the description of a single field within the packet
class PACKET_ITEM  :
    def __init__(self, field_name, type):
        self.field_name = field_name
        self.type = type;
        # self.offset = 0;
        self.position = 0;


if __name__ == "__main__" :

    INT32 = "l";
    UINT16 = "H";
    FLOAT = "f";

    packet_def = PACKET_STRUCTURE();

    # create an example packet structure - which is arbituary and could be anything - it could even be read from a file
    # this definition is the ONLY defintion of the packet structure
    # changes here require NO changes elsewhere in the program
    packet_def.add(PACKET_ITEM("time_sec", FLOAT))
    packet_def.add(PACKET_ITEM ("status",UINT16))
    packet_def.add(PACKET_ITEM ("position",INT32))

    # create a list of packets
    pk_list = list()
    for cnt in range(0,10) :
        pk_list.append(packet_def.make_packet());

    ################################
    # get the vectors without replicating the structure
    # eg no int32[] position = (int32[])get_vector()

    name_list = packet_def.get_names();
    for name in name_list :
        vector = packet_def.get_vector(name, pk_list);
        print name, vector

Answer 1

答案是将数组存储在 List<dynamic>

类型的集合中

集合中 returns 个元素的 return 类型的函数也应该是动态的。

这是此人试图澄清的 to my 。

如何return不同类型的数组？

How to return different types of arrays?

c#

python

arrays

strong-typing

data-structures