如何将字符串转换为字节而不进行编码 [英] How to cast a string to bytes without encoding

问题描述

我有一堆二进制数据通过char *从某个C接口（不在我的控制下）通过char *到达python，所以我有一串任意的二进制数据（通常是字节数组）。我想将其转换为字节数组，以简化与其他python函数的结合使用，但我似乎不知道如何操作。

I have a bunch of binary data that comes to python via a char* from some C interface (not under my control) so I have a string of arbitrary binary data (what is normally a byte array). I would like to convert it to a byte array to simplify using it with other python functions but I can't seem to figure out how.

不起作用的示例：

data = rawdatastr.encode（）这假定 utf-8并处理数据==不良

data = rawdatastr.encode() this assumes "utf-8" and mangles the data == BAD

data = rawdatastr.encode（'ascii'，'ignore'）去除超过127个字符==坏

data = rawdatastr.encode('ascii','ignore') strips chars over 127 == BAD

data = rawdatastr.encode（'latin1'）不确定-这是迄今为止最接近的参数

data = rawdatastr.encode('latin1') not sure -- this is the closest so far but I have no proof that it is working for all bytes.

data = array.array（'B'，[x for map in x（ord， data）]）。tobytes（）可行，但似乎要做很多简单的工作。有什么更简单的东西吗？

data = array.array('B', [x for x in map(ord,data)]).tobytes() This works but seems like a lot of work to do something simple. Is there something simpler?

我想我需要编写自己的身份编码，该编码只是将字节传递（我认为 latin1这样做了）

I am thinking I need to write my own identity encoding that just passes the bytes along (I think latin1 does this based upon some reading but no proof thus far).

推荐答案

尽管我怀疑还有其他东西正在为您解码数据（< C中的code> char * 通常最好用 bytes 表示，尤其是二进制数据时）：

Though I suspect something else is decoding your data for you (a char* in C is usually best represented as bytes, especially if it is binary data):

latin1 编解码器可以使每个字节往返。您可以使用以下简短程序对此进行验证：

The latin1 codec can round trip every byte. You can verify this with the following short program:

>>> s = ''.join(chr(i) for i in range(0x100))
>>> s
'\x00\x01\x02\x03\x04\x05\x06\x07\x08\t\n\x0b\x0c\r\x0e\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f !"#$%&\'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~\x7f\x80\x81\x82\x83\x84\x85\x86\x87\x88\x89\x8a\x8b\x8c\x8d\x8e\x8f\x90\x91\x92\x93\x94\x95\x96\x97\x98\x99\x9a\x9b\x9c\x9d\x9e\x9f\xa0¡¢£¤¥¦§¨©ª«¬\xad®¯°±²³´µ¶·¸¹º»¼½¾¿ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùúûüýþÿ'
>>> s2 = s.encode('latin1').decode('latin1')
>>> s2 == s
True
>>> sb = bytes(range(0x100))
>>> sb
b'\x00\x01\x02\x03\x04\x05\x06\x07\x08\t\n\x0b\x0c\r\x0e\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f !"#$%&\'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~\x7f\x80\x81\x82\x83\x84\x85\x86\x87\x88\x89\x8a\x8b\x8c\x8d\x8e\x8f\x90\x91\x92\x93\x94\x95\x96\x97\x98\x99\x9a\x9b\x9c\x9d\x9e\x9f\xa0\xa1\xa2\xa3\xa4\xa5\xa6\xa7\xa8\xa9\xaa\xab\xac\xad\xae\xaf\xb0\xb1\xb2\xb3\xb4\xb5\xb6\xb7\xb8\xb9\xba\xbb\xbc\xbd\xbe\xbf\xc0\xc1\xc2\xc3\xc4\xc5\xc6\xc7\xc8\xc9\xca\xcb\xcc\xcd\xce\xcf\xd0\xd1\xd2\xd3\xd4\xd5\xd6\xd7\xd8\xd9\xda\xdb\xdc\xdd\xde\xdf\xe0\xe1\xe2\xe3\xe4\xe5\xe6\xe7\xe8\xe9\xea\xeb\xec\xed\xee\xef\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9\xfa\xfb\xfc\xfd\xfe\xff'
>>> sb == s.encode('latin1')
True

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