CODEWITHSUNDEEP
pythondictionaryordereddictionary
exAres
exAres

Reputation: 4926

How to change keys of ordered dict to that of keys from other ordered dict in Python?

I have two ordered dicts D1 and D2. I want to assign key names of D2 to D1 (overwrite existing key names of D1). How to do that?

Example:

D1 = {'first_key': 10, 'second_key': 20}
D2 = {'first_new_key': 123, 'second_new_key': 456}

Now I want to assign key names of D2 to D1 so that D1 becomes

{'first_new_key': 10, 'second_new_key': 20}

Upvotes: 2

Views: 2638

Answers (3)

noamgot
noamgot

Reputation: 4091

here's a solution:

keys = D2.keys()
values = D1.values()
new_dict = dict(zip(keys, values))

If your'e into 1-liners (that's why we have python, right?):

new_dict = dict(zip(D2.keys(), D1.values()))

As mentioned in the comments, the insertion order between the 2 dictionaries must match.

EDIT

I figured out that you want to overwrite D1. In that case you can simply do:

D1 = dict(zip(D2.keys(), D1.values()))

EDIT 2

As Barmar mentioned in another answer, in order to have ordered dictionaries, one must use collections.OrderedDict().

Upvotes: 5

Barmar
Barmar

Reputation: 780899

noamgot's answer will work if it's OK to create a new dictionary. If you need to modify the existing dictionary in place:

for (old_key, old_val), new_key in zip(list(D1.items()), D2.keys()):
    del D1[old_key]
    D1[new_key] = old_val

The list() wrapper are needed in Python 3 because items() is a generator, and you can't modify the dict being iterated over.

DEMO

Upvotes: 2

Ajax1234
Ajax1234

Reputation: 71451

The simplest way is mere dictionary assignment:

D1 = {'first_key': 10, 'second_key': 20}
D2 = {'first_new_key': 123, 'second_new_key': 456}
D2['first_new_key'] = D1['first_key']
D2['second_new_key'] = D1['second_key']

However, for larger dictionaries, it may be better to use dictionary comprehension:

D1 = {a:D1[a.split('_')[0]+"_key"] for a, _ in D2.items()}

Output:

{'second_new_key': 20, 'first_new_key': 10}

Upvotes: 0

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