python的字符串是unicode字符

Question

What does Unicode characters in python 3 string mean?

Since Python 3.0, the language features a str type that contain Unicode characters, meaning any string created using "unicode rocks!", 'unicode rocks!', or the triple-quoted string syntax is stored as Unicode

from python doc.

for a string abc , does Python holds [61, 62, 63] in memory? (since a is U+0061)

Does unicode character mean unicode codepoints?

Answer 1

Does unicode character mean unicode codepoints?

Yes and no. It depends on the version of python, and how it was built.

For versions 2.2 to 3.2 inclusive, python supported both narrow and wide unicode builds (see PEP-261 ). On a narrow build, the unicode range is restricted to the BMP :

Python 3.2.6 (default, Feb 21 2016, 12:42:00)
[GCC 5.3.0] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> sys.maxunicode
65535

and so characters outside this range have to represented as a surrogate pair :

>>> s = '😬'
>>> ord(s)
128556
>>> len(s)
2

With the introduction of PEP-0393 , narrow builds are no longer supported in python3, and so one character is always equivalent to one code-point:

Python 3.5.1 (default, Mar 3 2016, 09:29:07)
[GCC 5.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> sys.maxunicode
1114111
>>> s = '😬'
>>> ord(s)
128556
>>> len(s)
1