有个疑惑

[bxb100]

python 中 id([1]) == id([2]) 为 True,这是为啥啊

[czheo]

性能优化，内部把 list 重用了吧。

[imn1]

id([1]) is id([2])

[bxb100]

@czheo tuple 为啥不会出现这种情况

[czheo]

tuple 是 immutable 的，没法重用

[bxb100]

@czheo id(()) == id(())返回的为 True

[bxb100]

@czheo list 是临时对象，内存会自动清理， tuple 不会，而且 ()和(1)存放地址区域不同

[HypoChen]

id(object)

Return the “ identity ” of an object. This is an integer (or long integer) which is guaranteed to be unique and constant for this object during its lifetime. **Two objects with non-overlapping lifetimes may have the same id() value.**

```
>>> id([1])
4391579520
>>> id([2])
4391579520
>>> a = [1]
>>> b = [1]
>>> id([1])
4391757944
>>> id([2])
4391757944
>>> id(a)
4391579520
>>> id(b)
4391641672
>>> id([])
4391757944
```