How to remove set element in copied object

Question

The following code removes a set element from a copied dictionary, yet both dictionaries are changed. How can have dic1 remain unchanged?

dic1 = {'a': set([1,2])}
dic2 = dic1.copy()
dic2['a'].discard(1)

Possible duplicate of [How to copy a dictionary and only edit the copy](http://stackoverflow.com/questions/2465921/how-to-copy-a-dictionary-and-only-edit-the-copy) — Andrés Pérez-Albela H., Nov 06 '15 at 04:38

score 2 · Accepted Answer · answered Nov 06 '15 at 04:35

2

import copy

dic1 = {'a': set([1,2])}
dic2 = copy.deepcopy(dic1)
dic2['a'].discard(1)

answered Nov 06 '15 at 04:35

score 1 · Answer 2 · answered Nov 06 '15 at 05:22

1

learn about copy — Shallow and deep copy operations to understand why copy doesn't work, but deepcopy works

answered Nov 06 '15 at 05:22

Hooting

2 Answers2