如何切片十六进制数据？

Question

我有十六进制数据，其中存在三个数据，我可以在这些数据上分离十六进制数据中包含的信息：

ID（2字节）
数据包长度（2字节）
信息

从数据包的长度，我们可以知道这个十六进制数据中的数据有多长 hex data = 0001001447364B5F48312E305F56312E312E3165000300133836333932313033343330343337310004000838303634000200154D414A3258584D524A32444A363135303900050005010006000843415244000700094341524431000800050000090018383939313035323138303935393533303834300D000A000E706F7274616C6E6D6D73

如果我们根据上面的信息手动分离这个HEX数据那么我们就得到这个数据 0001001447364B5F48312E305F56312E312E3165

这里

id=0001

数据包长度=0014=20

信息=47364B5F48312E305F56312E312E3165

我曾尝试通过我的代码来分隔信息，但它只分隔了第一个数据我想分隔整个十六进制数据

这是我的 python 代码：

data="0001001447364B5F48312E305F56312E312E316500030013383633393231303334333034333731"
t=data[0:4]
l=data[4:8]
hex_to_decimal=int(l, 16)
data1=data[0:hex_to_decimal*2]
print(data1)

谁能帮我算一下

Answer 1

这就是 struct 包的真正用途（和 bytes.fromhex）

>>> import struct
>>> s = "0001001447364B5F48312E305F56312E312E3165000300133836333932313033343330343337310004000838303634000200154D414A3258584D524A32444A363135303900050005010006000843415244000700094341524431000800050000090018383939313035323138303935393533303834300D000A000E706F7274616C6E6D6D73"
>>> mbytes = bytes.fromhex(s)
>>> msg_id,msg_size = struct.unpack(">hh",mbytes[:4])
# 1, 20
>>> msg_bytes = struct.unpack_from("{}s".format(msg_size),mbytes[4:])[0]
>>> msg_hex = bytes.hex(msg_bytes)
# 47364b5f48312e305f56312e312e316500030013
# which i think is what you actually want... but if you actually think size represents each character in that string you will need to make a modification
>>> alt_hex = s[8:][msg_size] 
# 47364b5f48312e305f56 ( which i think is the wrong value...)

Answer 2

您可以遍历 data 字符串并提取数据。

这是它的样子：

data="0001001447364B5F48312E305F56312E312E3165000300133836333932313033343330343337310004000838303634000200154D414A3258584D524A32444A363135303900050005010006000843415244000700094341524431000800050000090018383939313035323138303935393533303834300D000A000E706F7274616C6E6D6D73"

i = 0
while i < len(data):
    t = data[i:i+4]
    l = data[i+4:i+8]
    hex_to_decimal = int(l, 16)
    data1 = data[i:i+hex_to_decimal*2]

    print(f'Length: {hex_to_decimal*2}\nData: {data1}\n')
    i += hex_to_decimal*2

Output:

Length: 40
Data: 0001001447364B5F48312E305F56312E312E3165

Length: 38
Data: 00030013383633393231303334333034333731

Length: 16
Data: 0004000838303634

Length: 42
Data: 000200154D414A3258584D524A32444A3631353039

Length: 10
Data: 0005000501

Length: 16
Data: 0006000843415244

Length: 18
Data: 000700094341524431

Length: 10
Data: 0008000500

Length: 48
Data: 00090018383939313035323138303935393533303834300D

Length: 28
Data: 000A000E706F7274616C6E6D6D73

如何切片十六进制数据？

How to slice hex data?

python

hex

python-3.x