python 操作2个list，可变，list push和append 操作的是数组地址

[email protected]# python
Python 2.6.6 (r266:84292, Aug 18 2016, 15:13:37) 
[GCC 4.4.7 20120313 (Red Hat 4.4.7-17)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> arr1 = [1,2,3]
>>> tmp1 = arr1
>>> tmp1
[1, 2, 3]
>>> print tmp1
[1, 2, 3]
>>> arr1 = [0]
>>> print tmp1
[1, 2, 3]
>>> print arr1
[0]
>>> arr1 = tmp1
>>> print arr1
[1, 2, 3]
>>> print tmp1
[1, 2, 3]
>>> 

[email protected]# python
Python 2.6.6 (r266:84292, Aug 18 2016, 15:13:37) 
[GCC 4.4.7 20120313 (Red Hat 4.4.7-17)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> arr1 = [1,2,3]
>>> tmp1 = arr1
>>> arr1.pop(0)
1
>>> arr1.pop(0)
2
>>> arr1.pop(0)
3
>>> tmp1
[]
>>> arr1
[]
>>> tmp1
[]
>>> 

以上，

将tmp1 = arr1  ,如果用 list.pop() 方法，那么  arr1和tmp1 会同时 完成 pop

如果其中一个做赋值操作，另一个没有影响，不会同时变更。

同理，

将tmp2 = arr2 ，如果用 arr2.append() 方法添加元素，那么 arr2和tmp2 会同时 完成append

如果其中一个做赋值操作，比如 tmp2 = [7,8,9] ,那么 arr2 还是原来的值

>>> arr2 = []     
>>> tmp2 = arr2
>>> arr2.append(4)
>>> arr2.append(5)
>>> arr2.append(6)
>>> tmp2
[4, 5, 6]
>>> arr2
[4, 5, 6]

>>> arr2 = arr2 + [7,8,9]
>>> arr2
[4, 5, 6, 7, 8, 9]
>>> tmp2
[4, 5, 6]