python - 自增运算符 ++i 不会在 python 中导致错误

Question

既然python中不支持自增运算符++，为什么在给变量加前缀的时候不会报错。例子：

i = 3
++i

在交互式控制台上打印 3。这是为什么？

Answer 1

Take a look - it's just a sign:

>>> i = 3
>>> +i
3
>>> ++i
3
>>> +++i
3
>>> -i
-3
>>> --i
3
>>> ---i
-3

Answer 2

Python treats ++i as +(+i), that would compile fine, and print the same value as of i.