如何在 Python 3.4 中将 bytestring 数组转换为十六进制字符串？

Question

我有一个来自套接字连接的字节串：

>>> var
b'\xb5\x1a'

如何将此（小端顺序）转换为十六进制字符串，例如：

>>> var2
0x1AB5

我试过了：

>>> var.decode('utf-8')
Traceback (most recent call last):File "<stdin>", line 1, in <module> UnicodeDecodeError: 'utf-8' codec can't decode byte 0xb5 in position 0: invalid start byte

>>> var.from_bytes(2,'little')
Traceback (most recent call last):File "<stdin>", line 1, in <module> AttributeError: 'bytes' object has no attribute 'from_bytes'

Answer 1

int.from_bytes 方法会有所帮助。

int.from_bytes(bytes, byteorder, *, signed=False) -> int

Return the integer represented by the given array of bytes.

...

If byteorder is 'little', the most significant byte is at the end of the byte array.

它将字节转换为整数：

In [1]: int.from_bytes(b'\xb5\x1a', 'little') # 'little' for little-endian order
Out[1]: 6837

那你可以用hex

In [2]: hex(int.from_bytes(b'\xb5\x1a', 'little'))
Out[2]: '0x1ab5'

或format(..., '#x')

In [3]: format(int.from_bytes(b'\xb5\x1a', 'little'), '#x')
Out[3]: '0x1ab5'

获取十六进制表示。

其他解决方案包括base64.b16encode

In [4]: import base64

In [5]: '0x' + base64.b16encode(b'\xb5\x1a'[::-1]).decode('ascii')
Out[5]: '0x1AB5'

和binascii.hexlify:

In [24]: '0x' + binascii.hexlify(b'\xb5\x1a'[::-1]).decode('ascii')
Out[24]: '0x1ab5'

bytestr = b'\xb5\x1a'的一些时间：

In [32]: %timeit hex(int.from_bytes(bytestr, 'little'))
1000000 loops, best of 3: 267 ns per loop

In [33]: %timeit format(int.from_bytes(bytestr, 'little'), '#x')
1000000 loops, best of 3: 465 ns per loop

In [34]: %timeit '0x' + base64.b16encode(bytestr[::-1]).decode('ascii')
1000000 loops, best of 3: 746 ns per loop

In [35]: %timeit '0x' + binascii.hexlify(bytestr[::-1]).decode('ascii')
1000000 loops, best of 3: 545 ns per loop

对于bytestr = b'\xb5\x1a' * 100：

In [37]: %timeit hex(int.from_bytes(bytestr, 'little'))
1000000 loops, best of 3: 992 ns per loop

In [38]: %timeit format(int.from_bytes(bytestr, 'little'), '#x')
1000000 loops, best of 3: 1.2 µs per loop

In [39]: %timeit '0x' + base64.b16encode(bytestr[::-1]).decode('ascii')
1000000 loops, best of 3: 1.38 µs per loop


In [40]: %timeit '0x' + binascii.hexlify(bytestr[::-1]).decode('ascii')
1000000 loops, best of 3: 983 ns per loop

int.from_bytes 对于小字节字符串（可以预见）很快，binascii.hexlify 对于较长字节字符串很快。

如何在 Python 3.4 中将 bytestring 数组转换为十六进制字符串？

How can I convert a bytestring array in a hex string in Python 3.4?

python

python-3.4