python - 为何print（my）还会输出小写的x，y，z？为何输出的不是字符串？

Question

c=['x','y','z']

for my in c:
    my.capitalize()
    print(my)

在 IDE 中输出：

'X'
x
'Y'
y
'Z'
z

请问，my 不是已经都变成大写的了吗？ 为何 print（my) 还会输出小写的 x，y，z？

为何输出的不是字符串？

谢谢

Answer 1

my = my.capitalize()Write it like this and it will change. Strings are immutable, a new string can only be created to replace the old one.

Answer 2

Because capitalize is pure (escape

Look at the function signature

>>> help(str.capitalize)
Help on method_descriptor:

capitalize(...)
    S.capitalize() -> str

    Return a capitalized version of S, i.e. make the first character
    have upper case and the rest lower case.

It just returns a capitalized version of str without changing the original str

Answer 3

str is an immutable type, str.capitalize will not act on the original string, but will return a new string

Answer 4

print(*objects, sep=' ', end='\n', file=sys.stdout, flush=False)

This is Python's print function definition, that is to say, the end parameter is added by default, and its default is 'n', so it will wrap.