How to copy a dictionary and only edit the copy

Question

Can someone please explain this to me? This doesn\'t make any sense to me.

I copy a dictionary into another and edit the second and both are changed. Why is this hap

Answer 1

On python 3.5+ there is an easier way to achieve a shallow copy by using the ** unpackaging operator. Defined by Pep 448.

>>>dict1 = {"key1": "value1", "key2": "value2"}
>>>dict2 = {**dict1}
>>>print(dict2)
{'key1': 'value1', 'key2': 'value2'}
>>>dict2["key2"] = "WHY?!"
>>>print(dict1)
{'key1': 'value1', 'key2': 'value2'}
>>>print(dict2)
{'key1': 'value1', 'key2': 'WHY?!'}

** unpackages the dictionary into a new dictionary that is then assigned to dict2.

We can also confirm that each dictionary has a distinct id.

>>>id(dict1)
 178192816

>>>id(dict2)
 178192600

If a deep copy is needed then copy.deepcopy() is still the way to go.