Initializing a dictionary in python with a key value and no corresponding values

Question

I was wondering if there was a way to initialize a dictionary in python with keys but no corresponding values until I set them. Such as:

Definition = {'apple': , 'ball': } 

and then later i can set them:

Definition[key] = something 

I only want to initialize keys but I don't know the corresponding values until I have to set them later. Basically I know what keys I want to add the values as they are found. Thanks.

Answer 1

Use the fromkeys function to initialize a dictionary with any default value. In your case, you will initialize with None since you don't have a default value in mind.

empty_dict = dict.fromkeys(['apple','ball']) 

this will initialize empty_dict as:

empty_dict = {'apple': None, 'ball': None} 

As an alternative, if you wanted to initialize the dictionary with some default value other than None, you can do:

default_value = 'xyz' nonempty_dict = dict.fromkeys(['apple','ball'],default_value)