在Python 3中禁止/打印不带b’前缀的字节

Just posting this so I can search for it later, as it always seems to stump me:

$ python3.2
Python 3.2 (r32:88445, Oct 20 2012, 14:09:50) 
[GCC 4.5.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import curses
>>> print(curses.version)
b'2.2'
>>> print(str(curses.version))
b'2.2'
>>> print(curses.version.encode('utf-8'))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'bytes' object has no attribute 'encode'
>>> print(str(curses.version).encode('utf-8'))
b"b'2.2'"

As question: how to print a binary (bytes) string in Python 3, without the b' prefix?

Use decode:

print(curses.version.decode())
# 2.2

If the bytes use an appropriate character encoding already; you could print them directly:

sys.stdout.buffer.write(data)

or

nwritten = os.write(sys.stdout.fileno(), data)  # NOTE: it may write less than len(data) bytes

If we take a look at the source for , it looks as if the b'' is baked into the method.

The most obvious workaround is to manually slice off the b'' from the resulting repr():

>>> x = b'\x01\x02\x03\x04'

>>> print(repr(x))
b'\x01\x02\x03\x04'

>>> print(repr(x)[2:-1])
\x01\x02\x03\x04

If the data is in an UTF-8 compatible format, you can convert the bytes to a string.

>>> import curses
>>> print(str(curses.version, "utf-8"))
2.2

Optionally convert to hex first, if the data is not already UTF-8 compatible. E.g. when the data are actual raw bytes.

from binascii import hexlify
from codecs import encode  # alternative
>>> print(hexlify(b"\x13\x37"))
b'1337'
>>> print(str(hexlify(b"\x13\x37"), "utf-8"))
1337
>>>> print(str(encode(b"\x13\x37", "hex"), "utf-8"))
1337