How do we declare a single byte variable in Python? I would like to achieve the following result represented in C:
unsigned char c = 0xFF;
I would like to know if it is possible to declare an 8-bit variable in Python.
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3 Answers
Python doesn't differentiate between characters and strings the way C does, nor does it care about int bit widths. For a single byte, you basically have three choices:
- A length 1
bytes(orbytearray) objectmychar = b'\xff'(ormychar = bytearray(b'\xff')) - An
intthat you don't assign values outsiderange(256)(or use masking to trim overflow):mychar = 0xff - A
ctypestype, e.g.mychar = ctypes.c_ubyte(0xff)
The final option is largely for dealing with C functions through ctypes, it's otherwise slow/not Pythonic. Choosing between options 1 and 2 depends on what you're using it for; different use cases call for different approaches (though indexing/iterating the bytes object would get you the int values if you need to use both forms).
Comments
The answer depends on python version.
$ python3
Python 3.6.8 (default, May 6 2020, 12:04:35)
[GCC 4.8.5 20150623 (Red Hat 4.8.5-39)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> myba = bytes([0])
>>> myba[0]
0
>>>
$ python
Python 2.7.5 (default, Mar 20 2020, 17:08:22)
[GCC 4.8.5 20150623 (Red Hat 4.8.5-39)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> myba = bytes([0])
>>> myba[0]
'['
>>>
Comments
The answer depends on the python version.
$ python
Python 2.7.5 (default, Mar 20 2020, 17:08:22) ...
>>> myba = bytes([0])
>>> myba[0]
'['
>>> myba = bytearray([0])
>>> myba[0]
0
>>>
$ python3
Python 3.6.8 (default, May 6 2020, 12:04:35) ...
>>> myba = bytes([0])
>>> myba[0]
0
>>> myba = bytearray([0])
>>> myba[0]
0
>>>