【python】列表的複製問題

python開發面試題，列表的複製問題

1. In [14]: import copy
3. In [15]: b = [1,2,[3,4]]
5. In [16]: a = b[:]
7. In [17]: a[2][0] = 100
9. In [18]: b
10. Out[18]: [1, 2, [100, 4]]
12. In [19]: a
13. Out[19]: [1, 2, [100, 4]]
15. In [20]: a1 = copy.copy(b)
17. In [21]: a1
18. Out[21]: [1, 2, [100, 4]]
20. In [22]: a[2][0] = 200
22. In [23]: b
23. Out[23]: [1, 2, [200, 4]]
25. In [24]: a1
26. Out[24]: [1, 2, [200, 4]]
28. In [25]: a2 = copy.deepcopy(b)
30. In [26]: a[2][0] = 300
32. In [27]: b
33. Out[27]: [1, 2, [300, 4]]
35. In [28]: a1
36. Out[28]: [1, 2, [300, 4]]
38. In [29]: a2
39. Out[29]: [1, 2, [200, 4]]