如何通过在字符串中使用 \\u 或 \\U 转义来正确表示 python3 (3.6.1+) 中的补充 unicode 字符

Question

Recently I'm learing python and has encountered a problem with unicode escape literal in python 3.

It seems that like Java, the \\u escape is interpreted as UTF-16 code point which Java uses, but here comes the problem:

For example, if I try to put a 3 bytes utf-8 char like "♬" ( https://unicode-table.com/en/266C/ ) or even supplementary unicode char like "𠜎" ( https://unicode-table.com/en/2070E/ ) by the format of \\uXXXX or \\UXXXXXXXX in a normal string as followed:

print('\u00E2\u99AC')  # UTF-8, messy code for sure
print('\U00E299AC')    # UTF-8, with 8 bytes \U, (unicode error) for sure
print('\u266C')        # UTF-16 BE, music note appeares
# from which I suppose \u and \U function the same way they should do in Java
# (may be a little different since they function like macro in Java, and can be useed in comments)

# However, while print('\u266C') gives me '♬'，'\u266C' == '♬' is equal to false
# which is true in Java semantics.
# Further more, print('\UD841DF0E') didn't give me '𠜎' : (unicode error) 'unicodeescape' codec can't decode bytes in position 0-9: illegal Unicode character
# which I suppose it should be, so it appears to me that I may get it wrong
# Here again : print('\uD841\uDF0E')  # Error, 'utf-8' codec can't encode characters in position 0-1: surrogates not allowed

print('\xD8\x41\xDF\x0E')  # also tried this, messy code
# maybe UTF-16 LE?
print('\u41D8\u0EDF')  # messy code
print('\U41D80EDF')  # error

So, I could see that python "doesn't support supplementary escape literal", and its behavior is also weird.

Well, I already know that the correct way to decode and encode such characters:

s_decoded = '\\xe2\\x99\\xac'.encode().decode('unicode-escape')\
               .encode('latin-1').decode('utf-8')
print(b'\xf0\xa0\x9c\x8e'.decode('utf-8'))
print(b'\xd8\x41\xdf\x0e'.decode('utf-16 be'))
assert s_decoded == '♬'

But still don't get how to do it right using \\u \u0026amp; \\U escape literal. Hopefully someone could point it out what I'm doing wrong and how it differs from Java's way, thanks!

By the way, my environment is PyCharm win, python 3.6.1, source code is encoded as UTF-8

Answer 1

Python 3.6.3:

>>> print('\u266c') # U+266C
♬
>>> print('\U0002070E') # U+2070E.  Python is not Java
𠜎
>>> '\u266c' == '♬'
True
>>> '\U0002070E' == '𠜎'
True