python - 重新绑定(bind)引发异常的字符串对象意味着什么？

Question

Python 简介

String objects (byte strings, as well as text, AKA Unicode, ones) are immutable: attempting to rebind or delete an item or slice of a string raises an exception.

重新绑定(bind)引发异常的字符串对象意味着什么？

>>> a="hello"
>>> a="world"
>>>  

我是否刚刚成功将变量 a 从字符串对象 'hello' 重新绑定(bind)到 'world'？

谢谢。

Answer 1

您所做的是删除“hello”字符串对象并将其替换为“world”字符串对象。文档的意思是这样的:

>>> a="hello"
>>> a[3]="t" # does not produce helto
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'str' object does not support item assignment
>>>