Python change all keys of a dictionary

Question

How do I change all keys of a dictionary

code:

d1 = {'mango':10,
          'bananna':20,
          'grapes':30}
d1_new_keys = ['yellow mango','green banana','red grapes']
d1.keys() = d1_new_keys

present answer:

SyntaxError: can't assign to function call

expected answer:

d1 = {'yellow mango': 10, 'green bananna': 20, 'red grapes': 30}

Asked By: Mainland

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Source

Answer 1

What you’re doing is trying to set the function d1.keys() to a list thus the error. The best way to do this would be with dictionary comprehension:

d1 = {k: v for (k, v) in zip(d1_new_keys, d1.values()}

This would essentially create a new dictionary and set it equal to d1 where the keys come from the d1_new_keys list and the values come from the original d1

Answered By: gavinmccabe

Answer 2

Mixing my answer with the others, a shorter solution would be.

d1_new_keys must have all the keys.

d1 = {'mango':10, 'bananna':20, 'grapes':30}
d1_new_keys = {
    'mango': 'yellow mango',
    'bananna': 'green banana',
    'grapes':'red grapes' }

d1 = {d1_new_keys[k]: v for k, v in d1.items()}

Original answer:

Dictionaries are not ordered lists, so you can’t just change the keys.

What you have to do, is build a new dictionary with the new keys.

d1 = {'mango':10, 'bananna':20, 'grapes':30}
d1_new_keys = {
    'mango': 'yellow mango',
    'bananna': 'green banana',
    'grapes':'red grapes' }
d2 = {}
for d in d1:
    if d in d1_new_keys:
        d2[d1_new_keys[d]] = d1[d]
d1 = d2

Answered By: Angel

Answer 3

To update the dict (without creating a new one):

d1 = {'mango':10, 'bananna':20, 'grapes':30}

d1_current_keys = list(d1.keys())
d1_new_keys = ['yellow mango','green banana','red grapes']

for current_key_ix, new_key in enumerate(d1_new_keys):
    d1[new_key] = d1.pop(d1_current_keys[current_key_ix])

NOTE: beware of depending on the order of the keys.

Answered By: Juan Federico

Python change all keys of a dictionary

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